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Animorphs #29

The Sickness

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Something is very wrong with Ax. He's sick. And the Animorphs don't know what to do about it. They can't take him to a hospital. They don't know how to contact the Andalite home world. And Ax is dying.

Cassie and the other Animorphs come up with a plan. But it involves finding a new way into the Yeerk pool. There's just one problem: Jake, Rachel, Tobias, and Marco come down with Ax's sickness. And now, for the first time, Cassie is on her own. . . .

152 pages, Paperback

First published May 1, 1999

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K.A. Applegate

251 books487 followers
also published under the name Katherine Applegate

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Profile Image for Weathervane.
321 reviews7 followers
March 8, 2024
My my my.

Cassie books can be the best in the series, if they're allowed to be. Of all the Animorphs, Cassie is the one most conflicted by the fight against the Yeerks. She is not simply a whiny moralist, as many readers (and Marco) like to suggest. Yes, she can be annoying; yes, sometimes her actions are wrong, even though they are always guided by the best of intentions. But Cassie is the one Animorph who possesses not just human empathy, but interspecies empathy -- that warmth and tenderness towards animals holds her back at times, but that same mindset allows her to relate to sentient aliens, including the Yeerks. Especially the Yeerks.

Let's go back to The Departure. If we define a hero as someone who stands up for her principles, no matter the cost, then Cassie is perhaps the quintessential human hero of the Animorphs universe. She sacrificed her freedom to save the life of a little girl, but more than that, she sacrificed her body, her senses, her life and everything she knew, in order to show a Yeerk, one of the Enemy, that peace was possible, that understanding was attainable. Yes, one could easily make the argument that this was an immensely foolish decision; she risked the entire human race on a gamble. Perhaps this was arrogance on Cassie's part, as she trusted her intuition more than her rationality. (Though -- and this is a separate discussion -- Cassie's intuition is almost always correct.) I won't deny she is a deeply flawed person in this regard, but the fact remains that she gave herself up for her beliefs, and for the destiny of two strangers, one a mere alien slug. If that's not love, if that's not bravery, then I don't know what is.

So Cassie's compassion sowed seeds in The Departure, and here the flowers begin to poke their heads out of the soil. (They bloom later in the series.) The Yeerk Peace Movement is beginning to thrive, but Aftran, the Yeerk Cassie made her deal with earlier, is a hostage, and Visser Three is going to torture her until she gives up everything she knows about the Animorphs. All will be lost if she is not rescued. To make matters worse, Ax has contracted a potentially lethal illness, and will literally need brain surgery. I think few Animorphs books have raised the stakes as much as this one.

Unfortunately, Cassie transcends "hero" in this book and becomes Wonder Woman. Honestly, she accomplishes everything on her own and escapes with hardly a scratch. It's great to have dangerous situations for the Animorphs to wriggle their way out of -- I especially liked the part of the book where they traverse the water pipes; this was genuinely suspenseful -- but one has to marvel at the luck these kids possess.

My annoyance aside, the unreality of it all doesn't hurt the book too much. The plot with Mr. Tidwell and Aftran more than make up for it. Aftran's ultimate destiny is perfect, and foreshadows the Final Solution to the Yeerk problem.

I believe there's a lot of beauty in Cassie that goes unrecognized, because it's cool to be unflinchingly cynical. "Principles" are for the naive, yes? You gotta do what you gotta do, no matter the cost, right?

Well -- is it true?
Profile Image for Julie.
1,034 reviews297 followers
August 19, 2015
Ghostwriter: Melinda Metz.

Oh goshhhh what a great string of books -- I ploughed through several of them in a day, so I'll hopefully keep them straight. This one picks up after #19 The Departure, continuing Aftran's storyline and expanding the world with the revelation that, thanks to Cassie's earlier actions, there's now an expanding Yeerk peace movement within the ranks of the empire. As often happens, a two-fold problem emerges: Ax is incapacitated by a mysterious sickness that is going to lead to his horrific death if he doesn't undergo brain surgery, and Aftran has been captured and will be interrogated by Visser Three, thus revealing all of the Animorphs' identities.

In short, the shit has hit the fan, as always.

Soooo I said in my review for #28 that Cassie is fierce? This book takes that and propels it to a whole other level. At the halfway point, the entire rest of the team is put out of commission and Cassie has to complete not one, but two insane and impossible missions by herself. This is probably the first time that I'm a straight-up Cassie stan, pumping my fist for her and loving her deeply, fiercely -- she is so wonderful, and heartfelt but also strong. I do think she's such an important character, because she shows that you can be a strong female character without being a Strong Female Character, without having to love violence and battle like Rachel does.

I've disagreed with a lot of Cassie's earlier decisions, like how she dealt with Aftran in the first place, but it works out. It isn't blindly validating her choice -- the narrative and Cassie herself has always acknowledged how stupid it was -- but it's also acknowledging the importance of hope, cooperation, trying for something different, and breaking the cycle of violence.

Also, more Erek! Erek being wryly respectful with "Yes, ma'am." He's the best. I can't get over how much I love them using him and the Chee more often in these later books.

EDIT: Editing this review later to point out, because I forgot to mention it, how much I loved Cassie comforting Ax during his sickness, with an almost maternal air. It was really sweet, and showed a side of the Animorphs' friendship that we don't often get to see when they're always in the middle of flurries of battle.
Profile Image for Kara Babcock.
2,114 reviews1,593 followers
May 24, 2016
A sequel to #19: The Departure, The Sickness moves forward the Yeerk peace movement subplot. And I don’t know how you can possibly hate on Cassie after reading this book, because she literally saves the day single-handedly. She is boss mode.

I mean, if Cassie had been any more successful, she would be a Mary Sue. Not only does she infiltrate the Yeerk Pool, without any backup, by hosting a sympathetic Yeerk, rescue Aftran, evade capture, and make it out alive … then she proceeds to perform brain surgery on an Andalite without killing him.

So … yeah. That might be the best plot summary of an Animorphs book in a long time.

Not to mention, Cassie has the most adorable attitude while doing it: that kind of, “Ugh, I guess I’ll have to take care of this by myself—again” attitude super-capable people occasionally get when their friend reneges on a plan for the nth time because they are “sick” or something. With the other Animorphs out of commission thanks to a less serious form of the sickness gripping Ax, Cassie (it’s never explained why she is unaffected) is the only one able to do anything. The stakes are incredibly high: if Visser Three successfully interrogates Aftran, they will reveal the true identities of the Animorphs, and it is game over.

It’s no wonder Cassie wanted to quit the Animorphs ten books ago, and look at what she has had to go through since then. The Howler thing practically tore her up inside. And Marco is getting really insensitive with his jibes. So when Cassie has to step up, she does so in a big way, because she is ever the reluctant Animorph these days. And there are no thanks for her, no awards, of course, because this is a secret war. This book does a great job of describing the pressure a lone soldier can feel when an important mission hinges on their success.

I also love the ending. I think the way they manage to save Aftran without compromising another human being is excellent. Not only do they foreshadow it during the usual start-of-book exposition, but it has a kind of romantic righteousness to it. Of course this is how morphing technology could be used to end things.

But … but … the best thing about this book is, bar none, the ongoing developments in the Cake relationship. Jake “asks” Cassie to prom … well, OK, Rachel voluntells Jake to take Cassie to the prom. It’s pretty much the same thing. But the way that they are so sweet on each other is lovely here … and it is heartbreaking at the same time, this being my second read-through of the series, because we know what is coming. While I have no clear memories of any specifics from the finale, I know that it does not end well for Cake—and in retrospect, that makes sense. But in the here and now, things seem to be going so well. Oh, young, starcrossed lovers….

Next time, it’s another Megamorphs, which means … you guessed it … more time travel!

My reviews of Animorphs:
← #28: The Experiment | Megamorphs #3: Elfangor's Secret

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Profile Image for Choko.
1,500 reviews2,683 followers
August 3, 2024
*** 4.25 ***

Cassie always has a great POV! Yes, it's a bit outrageous with her giving it a try at brain surgery, but the ending was great and I am still enjoying these kids books 📚😃👍
Profile Image for Nemo (The ☾Moonlight☾ Library).
724 reviews320 followers
July 4, 2013
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Brought to you by The Moonlight Library!

Cassie and the Animorphs find out that their Yeerk ally Aftran has been captured and is going to be interrogated by Visser Three in a few days about the Yeerk peace movement. They decide to infiltrate the Yeerk pool and rescue her. Meanwhile, Ax falls ill with a deadly Andalite infection called yamphut, and it infects the other Animorphs as well. Cassie is left to infiltrate the Yeerk pool and rescue Aftran all by herself, and by the way also needs to perform brain surgery on Ax to save his life.

Out of the ghost written books, this is one of the better ones. As the Animorphs start dropping like the five little monkeys jumping on the bed, the leadership is handed from morpher to morpher. Cassie’s obviously not second or even third in command, and only takes charge when there is a medical reason. That being said, she manages to efficiently and dangerously rescue Aftran single-handedly and get them both out fo the Yeerk pool alive only to race home and perform brain surgery on a dying alien.

There is also some very neat and subtle foreshadowing that helps clue in to how the mystery of keeping Aftrain alive without access to Kandrona rays, and some moments of Cassie introspection when she admits she’s probably the only Animorphs that has wondered what it’s like to be a Yeerk, a blind, helpless worm.

Basically, Cassie is at her best in this book. She tends to do well when the leadership role is forced upon her. It also doesn’t hurt that she’s the best morpher and often complete these amazing feats under duress.

Even though Cassie was annoying in some of the earlier books with her moralising and navel-gazing, when she needs to take action she shines pretty brightly. Also, she makes the two biggest decisions in the entire series that pretty much change the whole game.

Although this book isn’t essential reading in the overall story arch, it is well worth the read to see Cassie kick a bunch of ass solo and see Aftran’s story arc concluded.

PS – the ghost writer for this book was the same author that wrote the Roswell books! (which I have not read.)
Profile Image for Trevor Abbott.
335 reviews40 followers
March 28, 2024
An animorph, a yeerk, and a chee all walk into a barn to perform brain surgery on an andalite

Wooooow Cassie actually did something herself for once. Maybe a redemption arc in her future?
Profile Image for Alan Gilfoy.
77 reviews1 follower
January 23, 2015
"Great character dynamics and action"

This book represented Cassie's personality very well.

I'm used to Rachel musing about her violent nature; Cassie wondering how peaceful she really is was an interesting analogue to that.

Cassie's sympathy for Yeerk sensory deprivation added something to the usual intro. Ax relishing the sensation of human morph was an interesting analogy that I'm glad Cassie brought up. I figured it was foreshadowing of Yeerks morphing.

The dance was comic relief. The main relationship development was that being liked by Jake helped Cassie feel good. "He's a popular type who doesn't care how plain she is" was reiterated.

Marco was right, something serious happened when they tried to do something fun.

At least Tidwell's interference was serious help rather than a just a convenient distraction or willfull ignorance on the part of observers. The series often seems to be guilty of plot holes of the latter variety.

It was clear that Illim became Tidwell's main companion. I took Tidwell's story as a reminder of why people were susceptible to The Sharing.

I can see how Marco thinks it's a trap to lure them in deeper, create a false sense of security. It's a another reminder of how I identify with his character.

Again, Cassie coached someone through a critical morph.

So there is some literal water in this pool. How do the Yeerks get away with taking it from the grid? Controllers at a utility? The water version of stealing cable or other such services? This all reminds me of the truck ship from #3 The Encounter. Maybe that couldn't make covert deliveries underground in an occupied area.

Rachel calling eels in the pipe a water slide sounds like Marco rubbing off on her.

"Oh god it's spreading" worked as a delay to that particular mission as well as a general challenge. Yamphut seeming flu-like may be a contrivance to hide evidence of aliens, but it's relatively believable, at least by the standards of this series.

I could tell Cassie wouldn't be able to pull off the surgery by herself. I'm reminded of a conversation about the series where it was said that #29 would have been an especially good time to tell the truth to the Animorphs' parents.

I thought an Animorph with a hostile Yeerk might be able to infiltrate the YPM. Since that didn't happen here, I wonder how it was done. Maybe an ordinary Yeerk/Controller went in as a double agent. That could be used to catch other YPM members. However, none of them would know what Aftran and Illim would know. I assume Aftran was smart enough to not tell other YPM members too much - and Illim too, but he wouldn't yet have had time to talk anyway. Since Visser Three wanted information, I can see how Aftran wasn't killed instantly, and the visser did hustle to take care of it. Often villains let heroes live in order to gloat and this backfires.

It was interesting to hear that Yeerks have some survivability in non-Kandrona water.

I figured Yeerks might rush to grab a host, as we see with Cassie in morph. That might be useful for new/random hosts instead of reinfestations and special hosts. I wonder how they go about getting a particular Yeerk for a particular host. I recall messages being sent to Esplin Yeerk-to-Yeerk in the Hork-Bajir Chronicles, but I wonder if that could be an everyday thing. The Yeerks would figure it out if someone gets the wrong host, so none of the slugs do that on purpose.

Aftran as a whale nothlit would have been a surprise without hindsight, so that seems well-written. Yes, that's a very good idea all around. it seems they're trying not to think about David. This is one of the few times he's been alluded to since the trilogy was wrapped up.

This book showed team dynamics via the lack thereof.
Profile Image for Liv.
442 reviews48 followers
March 21, 2024
"she had done what few have the strength to do. she had questioned the beliefs she had been raised with. and ultimately, she had chosen to go against her society. to turn away from everything she had once believed, to become the enemy of those closest to her."

the fundies were right to freak out abt these books
Profile Image for Jenny Clark.
3,225 reviews122 followers
May 20, 2017
So, this is another one I remember vaguely from childhood. I knew how Aftran's story ended!

Anyways... I enjoyed this one a good bit. It wrapped up an otherwise open plot point, which is pretty cool in a series this long.

There was a lot of action in this one. The stakes keeping getting higher and higher.

One question I have- I know the series takes place over 3 years, and the kids are 16 at the enhighd, so shouldn't they be in high school by now? They should be 14 at this point, I should think, since it's over halfway in the series...
Profile Image for Thibault Busschots.
Author 6 books206 followers
July 25, 2022
Ax is sick, something is wrong in his brain and it can kill him. The mission is very suspenseful and the stakes properly feel high. Though Aftan the Yeerk is not a character I love to see return. The beginning is also really sweet as we get to see the Animorphs in their natural environment, doing kids stuff. All the while we’re also getting another look at their personal relationships and development.
Profile Image for Muffin.
343 reviews15 followers
June 8, 2022
This one ruled. Cassie saves the day while juggling impossible moral questions, and we get more of the Yeerk resistance, AND alien brain surgery!! Great book, had me at the edge of my seat.
Profile Image for  Bon.
1,349 reviews198 followers
February 5, 2023
Fond memories of this one - so high octane and stressful!
Profile Image for Juushika.
1,831 reviews220 followers
February 27, 2019
I wish this book were ten pages longer, to give more time to the numerous ethical issues of morphing/possessing sentient beings--not just because it's in Cassie's wheelhouse, but because consent is a central theme. Further, I'm not entirely convinced by the experience of a Yeerk morph, which is heavily informed by an instinctual desire to inhabit a host. Where's that gray area of sentient morphs, which are uncomfortably devoid of animal instinct? I make these complaints because this book is inches from greatness, and I want it to reach that--but it's still so good. The illness B-plot is top grade tropey feels; Cassie's A-plot is punishing and engages all my symbiont feelings. This book feels ghostwritten with love--Metz grabs on to interpersonal and worldbuilding elements that I really enjoy. And the ending left me teary-eyed.
962 reviews4 followers
June 14, 2020
The Animorphs reread continues! This one was one of my favorites as a kid. Cassie really gets to shine, and the plot is really cool. It was also a definite win they all got to feel good about. The morphs were also pretty awesome. I also liked Tidwell's involvement.
Profile Image for Nikki.
351 reviews68 followers
October 6, 2016
I always love seeing Cassie take charge, because I know it's something she struggles with. One of the better ghost written books for sure.
Profile Image for The Library Ladies .
1,662 reviews83 followers
May 30, 2018
(Full review here at the thelibraryladies.com.)

Narrator: Cassie

Plot:

Reading the plot description, I remembered that this was the one where everyone got sick and somehow Aftran, the Yeerk Cassie has a soul-search with back in book #19 (“Serena’s RAGE book,” as I’ve come to think of it), was somehow involved. But I am happy to report…

The story starts out with actually a fairly long portion of the kids in real life doing real kid things. Like Cassie and Jake continuing to be ridiculous with their burgeoning relationship when it comes to school and dances. With some kicks to the butt offered by Rachel, the team all end up at the dance with the various couples all pairing up. As they dance, Rachel and Cassie notice Ax growing a sudden protuberance on his head: a stalk eye! The group rush him out of the gym, all while frantically trying to cover up his emerging Andalite bits. Ax is also delirious and mumbling incoherently. In the hall, Ax makes a wild bolt for it just as Chapman and a teacher, Mr. Tidwell, come around the corner. Mr. Tidwell takes one look at Ax and quickly tells Chapman that Ax must have been drinking, and crab-walks Ax back towards the group. The others grab Ax away as Marco and Rachel try to convince Tidwell that Ax is just sick and they need to take him home. But as they try to get past him to the door, Ax’s tail shoots out and whacks Tidwell on the head.

Tidwell grabs Cassie and walks her back down the hall. There, he confesses that he knows Ax is an Andalite. What’s more, Mr. Tidwell is a Controller, but not just any Controller. He and the Yeerk in his head are part of the Yeerk Peace Movement organized by none other than Aftran, the Yeerk Cassie saved way back when. But Aftran has been captured and Visser Three is on his way to interrogate her personally, likely exposing all of the Animorphs in the process. For now, she’s being held in the Yeerk pool, but Tidwell insists that Cassie and her friends have to rescue her, for the sake of themselves and the entire Yeerk Peace Movement.

Cassie rejoins the group and they manage to get Ax back to Cassie’s barn. There, in a moment of clarity, Ax explains that Yamphut, a disease that infects the Tria gland in his brain and can cause it to explode. The only way to save him will be to remove the gland when his temperature goes back down. Yamphut is also contagious to humans, but in them it just presents as a common flu.

Cassie then also explains about Aftran. Marco and Rachel are particularly harsh about reminding her that it was her choice to give them all up to Aftran that lead them to being in this current situation. They decide they need to get into the Yeerk pool tonight, hopefully returning before Ax’s temperature dips to the crisis point. In the meantime, they call in Erek to hang out with Ax in the barn, projecting a hologram of an empty stall so Cassie’s parents don’t discover him.

But to get into the Yeerk pool, they now need to get past the new security system that attacks all biological life that isn’t controlled by a Yeerk. Marco has the idea to use the sewer system, reasoning that the Yeerk pool is like an entire city, so there must be plumbing connecting it to the outside world. Tobias then comes up with the idea of using an eel morph and he retrieves one from a local bait shop that he knows of. With Erek’s map of the city plumbing system in their minds, the team find themselves up in water tower, ready to use the extra force of the water to propel them where they need to go.

In eel morph, the team rush down the pipes. It’s a wild ride with them barely making all of the turns they need to. Suddenly, Jake is sucked into the wrong pipe. Forming a line, the others manage to pull him back out. But they realize that something is wrong with him, that he has come down with the same sickness. After some debate about whether they should split up, they all decide they have to abort the mission. They manage to ride the strongest currents they can find and end up getting shot out of a fire hose and into a burning building. There, they all de-morph and re-morph birds to escape. Jake, now violently sick, heads home with Cassie and Marco to help him.

The next day at school, Rachel is no where to be found. Turns out she came down with the “flu” last night as well. Mr. Tidwell catches up with Cassie in the hall. He explains how dire the situation is becoming, Visser Three has moved up his visit, and that the other Yeerk Peace Movement members can’t do much. Many of them don’t have hosts (since they are committed to finding hosts that want to team up with them) and many of the others, like Tidwell, are in bodies that can’t fight. Desperate, Cassie comes up with a new plan: they can morph Yeerks.

On the way home, Marco, too, gets sick. But he also points out the one flaw: what happens if they do save Aftran? She’ll just die of starvation. Back in the barn, Tobias says that Ax’s temperature continues to drop. He then flies off to check on the other patients, which Cassie reads as him wanting to go check on Rachel. Cassie looks around the barn for tools, mentally preparing herself for the fact that she’s going to have to do brain surgery on Ax eventually. As she gathers things, Tobias swoops back in, but he’s clearly not well and accidentally flies into a rafter, knocking himself out. He’s sick too. Cassie picks him up and puts him in a cage, figuring that her parents will think they just have one more rescued animal.

Cassie bikes to Mr. Tidwell’s house. There she puts her plan in action. Tidwell’s Yeerk comes out, Cassie acquires him, and begins the morph. In Yeerk form, she’s blind and deaf, but does have a sort of sonar. Tidwell picks her up and put her to his ear where she slithers in. She connects to his brain and regains her senses. It takes her a bit to figure out how to move Tidwell, who’s voice she can hear urging her to hurry up. She also can see all of his memories and feels ashamed that she is essentially violating his privacy.

Tidwell!Cassie then makes her way to the local McDonald’s, one of the known Yeerk pool entrances, hiding the original Yeerk on her person. She gains entrance and successfully gets past the security system. The Yeerk pool is as horrifying as ever. At the peer, she releases the Yeerk and slithers out of Tidwell’s ear herself. In the pool she is able to locate Aftran just as Visser Three arrives to collect her. She manages to demorph to human and then remorph as an osprey, the only bird morph she has that dives into water so can handle flying while wet. She grabs Aftran and barely manages to escape the pool. Conveniently, another Controller is entering up in the McDonald’s, so she is able to escape out before the security system fries her.

Back at the barn, Ax has reached his crisis and Cassie must operate. She quickly decides to have Aftran Control Ax so that she can tell Cassie from inside where exactly in Ax’s brain the Tria gland is located. Together, they are able to successfully remove the gland. Ax awakens just as Aftran exits and is horrified that he was infested. But now Cassie has another challenge: what to do with Aftran?

A few days later, the team are all recovered and walking along the beach. Out in the ocean, a humpback whale leaps before heading out to sea. They all agree that they used the blue box the right way this time. They let Aftran gain morphing powers if she agreed to trap herself in a morph. Whale!Aftran is now free.

Peace, Love, and Animals: This book definitely played to some of Cassie’s strengths. More so than most of the other characters, Cassie is probably the best character to describe what their lives are like as ordinary kids. Through her eyes, we’ve seen a lot more scenes of what school is like for the group and the various dynamics that exist between them outside of missions. Here, there were some very nice moments where Cassie was just an ordinary teenage girl, feeling awkward about her quasi-relationship with Jake and the fact that none of the girls at school know they are together (or even believe it could ever be possible!) So small moments, like her pride when they dance together, are just very sweet.

I also like the fact that we finally have circled back around to the aftermath of her decisions in book #19 when she left Aftran infest her and exposed them all. Here, she is much less confident that this was in fact the right choice. She admits that it felt right then, but the situation that they’re in now calls that all into question. There’s a very real possibility that they will all be exposed and killed simply because of that choice. Even with Aftran’s cooperation, here, Cassie sees that she is still a risk point for the group. She never outright regrets her decision in that book, but I like the fact that here she had to confront the reality of that choice a bit more head on. Also, when she is alone right before the mission, she is forced to leave Ax right before it seems like he is going to hit his crisis. She tells him that she has to save the group first, and tells Erek that if things go south, he has to just let Ax die rather than expose them. These are hard choices, but it’s nice to see Cassie confront them. Though, again, this calls into question my ongoing frustration with her character. She is completely inconsistent in her decision making and ability to prioritize individuals and her morals and the entire group/world. Sometimes she’s willing to throw everything away to make a stand on something, like quitting the team and telling Aftran their secrets, or letting the aliens re-direct the asteroid in Megamorphs #2. And at others, she’s willing to make the tough calls. I dunno. It just feels like I never know which Cassie I’m going to get.

But there’s no denying the coolness of her ability to successfully perform brain surgery on Ax. The idea of using Aftran to get a sense of things was great, but it still rested on her ability to pull it off. Without Cassie, Ax definitely would have been done for, as no other member of this group could have done what she did here.

Our Fearless Leader: Jake is out of commission very early in this book, which makes sense. In order to sow the most confusion, you have to take away calm, collected, Jake. Even in the midst of his burgeoning illness, when they’re in the pipes as eels, the others still are relieved when he manages to come to enough to tell them what to do.

Xena, Warrior Princess: It’s always fun to see Cassie and Rachel at school, and here Rachel takes things into her own hands about Cassie/Jake’s secret relationship. It also becomes clear that there is an unspoken hierarchy in leadership within the group. When it first becomes clear that Jake is getting sick, Rachel immediately steps into the leadership role. There’s some snark, but they all seem to kind of agree that this is right. And I know there’s a later book that focuses on this point, too. Other than that, she gets sick second, so doesn’t have too much to do.

A Hawk’s Life: When Ax gets sick at the school, while the others all fret about whether or not Mr. Tillman saw him, Tobias is the one clearly most worried about just Ax, forget everything else. He also gets sick, and I think it’s understood that this is because he is in human morph when Ax first comes down with it, and thus susceptible to infection.

As we’ll see in Marco’s section, he’s third in line for leadership, after Jake and Rachel. So leadership goes Jake, Rachel, Marco…? But honestly, given what we’ve seen from past books, I’d say leadership should go Jake, Tobias, Marco/Rachel, Ax, Cassie. Tobias has proven himself to be the most even-keeled of the group, he’s a good strategist (as proven in his book with the Hork Bajir valley), and he’s willing to make the tough calls (as seen in Megamorphs #2). Marco is probably the only one who would prove a problem, just because they tend to clash with Tobias not really appreciating Marco’s cynical outlook on things. But other than that, I think he’s a strong candidate for the role. I put Marco and Rachel together because, as we see in her book, this is kind of a tough role for her to fill. So Marco might make a bit more sense, simply because he’s a more level-headed player. But, it should be said, a big part of leadership is simply stepping up, unasked. Tobias has done it in the examples I gave above. And Rachel does it here, and will do it later. So it’s a tie.

The Comic Relief: Marco has some good lines in this book, and it is notable that he (along with Rachel) is the most critical about Cassie’s past decision with Aftran that lead to them being in this tough situation. He also comes up with the eel plan, which is clever, if not fully thought out. After Rachel goes down sick, Marco asks Cassie if this means that he’s now in charge.

In a nice reminder to Marco’s particular hatred of David, when they are on the beach in the end discussing their use of the blue box, we get this exchange:

“We made the right decision,” Jake said. “Better than the last time we used the blue box.”
“Would have been hard to do any worse,” Marco said.

E.T./Ax Phone Home: Poor Ax. It’s never really explained how he was exposed to this disease, but it seems kind of like the Andalite version of appendicitis. Some gland becomes painful and if it bursts, bad things follow. Of course, the tension must be raised by placing this gland in his brain. And then, in the midst of fever dreams, he’s the only one who can even marginally explain what is going on. Beyond that, he’s still a kid! Imagine some teenage boy trying to tell a doctor how to operate on him for appendicitis! Ax is also completely horrified when he discovers Aftran in his head immediately after waking up; he even goes so far as to say he wishes Cassie had just let him die. Cassie does a good job slapping some sense in him, but I don’t remember if Ax ever refers to this in future books. But it seems like something I’d want to hear his thoughts on.

Best (?) Body Horror Moment: Cassie morphing the Yeerk was particularly bad. She describes it as first having a layer of mucus ooze out of her pores until it covers her entire body, and then rest of her just kinds of melts away. But…mucus….all over body…I mean, I guess the process of morphing Yeerks should be one of the worst, and if that was the goal, then well done! Also, the process of infesting Mr. Tillman. Obviously the Yeerk instincts are fine with this, but I imagine there’s a pretty disturbing element to the thought of climbing into another human’s head through their ear, when you’re a human yourself only in morph.

Couples Watch!: Cassie has a very real teenage girl moment when she’s dancing with Jake, reveling in the fact that the other girls will now see that shy, animal-poop-covered Cassie is the one who gets to be with fairly popular Jake. Cassie also acknowledges the fairly official relationship status between Rachel and Tobias, hoping that they can get away to dance, too. And then later, she knows that it is really Rachel, not “the others,” that Tobias wants to check on when he flies off.

If Only Visser Three had Mustache to Twirl: Visser Three makes his token appearance towards the end, and it has to be one of the shortest cameo’s we’ve gotten from him one of these. He does make a very good point about osprey!Cassie’s escape while being shotat my multiple Controllers at the end:

I heard Visser Three roar.
Adult Ugly Crying at a Middle Grade Book: Not much! We all knew Ax was never in any real danger at this point, so while it was a good motivation for events, it didn’t have a lot of emotional impact. The scene of whale!Aftran was probably the most emotional bit of the book.

What a Terrible Plan, Guys!: There were some clever plans here, mostly Cassie coming up with the idea to use Yeerks as a morph to get into the pool, and then getting Aftran to help with the brain surgery. But man, that eel morph plan was not well thought out. I mean, it’s a cool idea and props to Marco for having the creativity to come up with it, but what was the end game there? How exactly were they going to get out, and with Aftran in toe none the less?? Even Cassie’s plan failed to have an exit strategy, and the fact that she wasn’t shot is pretty unbelievable.

Favorite Quote:

Mandatory Rachel/Marco banter:

“I just had a thought,” Marco said.
“I’ll buy you a card to commemorate the moment.” Rachel, of course.
In the very beginning, when Marco and the others are discussing just going to the dance like regular kids:

“Oh, man,” Marco moaned.

“What?”

“Every time we try to do something nice and normal it ends up turning out nasty and weird,” he said. “Every single time.”

Scorecard: Yeerks 6, Animorphs 12

No change! It’s a big win for the Animorphs to just survive this situation, but as far as actual damage goes, there’s not a big change. The Yeerk Peace Movement is a good thing to now have, and maybe indirectly through Cassie and Aftran, the Animorphs are responsible for it, but not much.

Rating: For the most part I did enjoy this book. I really liked the follow-up on the Aftran situation and the introduction of the Yeerk Peace Movement. Cassie, too, has some good moments in this story. I do wonder at these choices to continue to give Cassie books where she is isolated from the rest of the team for some reason or another. She simply doesn’t have the strongest voice of the group. Her narration is usually pretty straightforward and not very nuanced. She’s simply not as interesting to read about as say Marco, Ax or Tobias. So it’s strange that she seems to routinely get books where she’s all by herself and much of the story’s appeal (or lack there of) is left to her characterization. Obviously this is a story that had to belong to Cassie, and if it was the only example of her as an isolated character in these books, then fine. But this is like the 3rd book where she’s mostly on her own for a lot of it, and it’s just not the best.
Profile Image for Caroline.
352 reviews33 followers
April 16, 2024
Many times, I've disagreed with Cassie's decisions and her strict pacifist ways which can be maddening compared to the others' personalities and past decisions in previous books, especially in life-and-death situations, where the others are more ruthless and calculating.

Overall, her actions in The Departure are planted here that I hope the Animorphs and even Cassie are grateful for her compassionate nature and her unexpected bond with a Yeerk, Aftran 942, whom Cassie learned that NOT all Yeerks are evil and two dimensional and it's in this book that we learn as an audience what Cassie's influence has made in the long term.

Plot
Mr. Tidwell, one of Cassie's teachers, informs her that Aftran has been captured by Visser Three. She will be tortured, and will thus be forced to divulge all of her secrets; including that of Cassie and the Animorphs. Cassie endures her friends' thinly veiled blame, but they decide to act.

But there's a HUGE hurdle. Ax is sick, and suffering from an inflamed Tria gland, much like the lymphatic tonsils in the human mouth. Unlike humans, though, this gland is located at the back of Ax's brain. If it bursts, it will cause irreversible and fatal damage to the brain, most likely killing him. Cassie hides the sick alien in her barn, and Erek the Chee erects a hologram around them both.

Yay! Erek the Chee is back! Love seeing this recurring character back again as he helps the Animorphs by caring for Ax (and later Tobias), hiding them from Cassie's parents, and later aiding both Cassie and Aftran 942 in Ax's surgery, saving his life.

Unfortunately, everyone becomes sick with flu-like symptoms, leaving Cassie, the only Animorph member, healthy and alone in not only saving Ax's life but Aftran's, the Yeerk Peace movement, the Animorphs, and their families freedom and lives.

Cassie, with the aid of Mr. Tidall and his Yeerk Illim, willingly exits his host to enable Cassie to morph his Yeerk body so she can take over Mr. Tidall's body to infiltrate the Yeerk Pool to save Aftran 942's life, which she is successful despite Visser Three and the Yeerks' attempts to stop her, as a one woman's mission, not bad at all, though its only by pure luck.

Back at the barn, Cassie learns that Ax is in crisis, with Erek's help she operates, but Cassie makes an unthinkable solution to aid with the surgery, knowing full well that if Ax was conscious he wouldn't approve but also demonstrates Cassie's perceptions of the long term, she can't operate on Ax by herself and she allows Aftran to enter Ax's head and tell her the location of the Tria gland, showing that humans/Yeerks CAN collaboratively work together, that these two made the impossible happen that started in The Departure: hope, cooperation and having the bravery to break the cycle of violence.

Cassie and Aftran 942
It was awesome to see the strength of friendship/comradeship between Aftran 942/Cassie, the deep level of respect they have for each other, and Cassie's desperation to save her/it from capture and death, to where the Animorphs feel deep gratitude, to the point where there's unanimous agreement to give Aftran 942 the ability to morph to gain her freedom on the condition she becomes a nothlit: a form of a humpback whale.

"Aftran had sacrificed so much. She had experienced all the richness and wonder of our world. But when she decided she did not have the right to control another, she had been strong enough to give it up to save a little girl's life. She returned to the Yeerk pool. It must have felt like the worst kind of prison to her after being in Karen's body. But she didn't allow herself to wallow in despair. She chose to fight. She battled to free us all."
―Cassie


This pretty much sums up Aftran 942's personality and a beautiful conclusion to her/it's character arc as her initial meeting with Cassie and her experiences inspired her to create the Yeerk Peace movement with other like-minded Yeerks and find another way to co-exist with humans, a true symbiotic relationship (similar to the Tok'ra in the Stargate series)

Time for the next book!
Profile Image for Grapie Deltaco.
843 reviews2,612 followers
April 20, 2022
There’s a sickness spreading to the members of the Animorph team, starting with Ax. Navigating fevers, delirium, and morphing spasms, the team not only have to find the cure, but also assist a converted Yeerk during her interrogation.

With Cassie being the only Animorph left standing (and the only Animorph trusted by the members of Yeerk revolution for peace) we witness a grotesque morph and a shift in leadership capabilities from her.

It’s the sequel to the immense level of empathy and patience exhibited from her in Animorphs #19 (The Departure). We bear witness to an unthinkable change in moral code and character in a member of the Yeerk army, seeing the promising results from Cassie’s earlier sacrifice.

Cassie consistently manages to experience some of the most unhinged, out-of-left-field plot points and come out (somewhat) unscathed. The distinctions between her and Rachel are glaringly clear in her most memorable installments.

CW: war, slavery, violence, reference to dead loved one, brief moment of grief, brief moment of suicidal ideation
Profile Image for Swankivy.
1,193 reviews150 followers
August 6, 2014
Everybody but Cassie gets sick, leaving her alone to fight on an important mission, only to come home to perform brain surgery on Ax because Andalites don't puke. Bird poop saves the day!

Notable moments and inconsistencies:

This book is ghostwritten by Melinda Metz.

It's clear that the Yeerk Aftran has managed to start a peace movement somehow, but it's not clear how she was answering for not being in her host, who was supposed to be a young girl named Karen planted to watch the girl's dad and report on him to the Yeerks. It was never explained why Aftran managed to survive as long as she did in the Yeerk pool without being in her host.

Cassie again refers to her human form as her "human morph," which is inaccurate.

It's interesting that when Cassie has to do this mission all on her own, she assumes a lot of the roles of the others: saying "let's do it!" like Rachel, making dumb jokes to herself like Marco, and leading the way/making decisions like Jake.

It's not clear why Cassie of all people was the one who never got sick. If the flu was so contagious, why didn't she or anyone else around them get it? Because it was a bit too convenient, this felt more constructed than it should.

Cassie, despite her experience doing veterinary care for animals, does not have the experience to do brain surgery. Cassie performs major surgery in a later book as well, and neither book includes realistic detail about blood loss or any mention of anesthesia. Despite being an alien and in a delusional state, there's no reason Ax would not have had some realistic pain reaction to having his head drilled into.
Profile Image for Kate Crabtree.
347 reviews8 followers
November 17, 2020
There’s a little bit in the middle of The Sickness in which Jake gets sick, and Rachel immediately declares herself leader for the time being. And then Rachel gets sick, leaving Marco to declare he’s leader. Save for Tobias, who gets sick shortly after, Cassie is the only Animorph to not try and lead, and yet this badass manages to pull off a very risky mission and perform brain surgery on an alien... all in her own. She’s not given enough credit.
Profile Image for Cienna.
587 reviews8 followers
February 13, 2023
Girl becomes slug creature and causes adult man to vomit profusely.
Profile Image for Molly.
229 reviews4 followers
September 22, 2024
Cassie’s controversial decision in The Departure comes to fruition in The Sickness. This book feels like a direct sequel to The Departure, with either a vindication or a redemption arc for Cassie, depending on how you saw her choice in #19.

Throughout, she continues to show her tenderness and compassion as she cares for Ax and the other sick Animorphs. She advocates for Aftran and hearing out Mr. Tidwell. She comes up with the beautiful solution for . And she’s willing to morph a Yeerk, the enemy the Animorphs have been fighting for 29 books: an act with no small amount of empathy baked in. We also get some poignant moments, like when her father “catches” her “pretending to be a horse” – a glimpse into Cassie’s childhood that makes her current ability to become an animal, but only for the express purpose of doing violence, a real monkey’s-paw situation.

The story in The Sickness is one of the best of the last several books. The setup of the two ticking time bombs (Ax’s illness and Aftran’s interrogation) drive the plot forward wonderfully. There’s a sense of urgency and danger that’s heightened every time another Animorph falls ill. Also, the Yeerk resistance movement is such an interesting idea, and I love how the “good” Yeerk inhabiting Ax’s mind is impossible for his wartime programming to accept.

Miscellaneous thoughts:
- Strangely, the only part of this book I remembered from previous reads was the eel journey through the city water pipes. That adventure didn’t even get the Animorphs anywhere; it must have just stuck in my mind as such a vivid scenario: whooshing down pipes totally blind, making split-second life-or-death decisions.
- Is Cassie why I love humpback whales? (Could it also be reading Deep Wizardry at a young age?)
- Can Tobias just show up to a school dance? Isn’t he still, like, a missing person? Or did that get resolved when he almost went to live with “his cousin” in The Pretender?
Profile Image for Michael David.
30 reviews
February 22, 2025
This is without any doubt the most beautiful book in the series thusfar. That may be surprising to many, knowing that all of the Animorphs save for Cassie get horrendously sick and, in the meantime, Cassie morphs a Yeerk to execute a rescue mission in the Yeerk pool-- which is perhaps one of the ugliest places this series takes us.

I genuinely do not think there is a single flaw in how this story was executed. It was a marvelous idea, and I am well aware that this series can take a great idea like this and deliver short (primarily due to the limitations in how long these stories are, no doubt). However, this absolutely nailed it.

It is very nice to see a follow-up to one of Cassie's best books, *#19's The Departure,* where we get insight into how the Yeerk Peace Movement is progressing. It certainly was a very deserving book to get additional plot threads for because of the nature of what is explored. That is perhaps what makes Cassie books some of the best in the series (I will stand on business with those who say otherwise). While just about every Animorph struggles with how they perceive the war, Cassie tends to deeply explore the moral principles of what this war means. It obviously tracks, then, that her books definitely tend to be the most interesting from a philosophical perspective.

Although, for this particular book I would argue that these themes of morality absolutely take a backseat for the sake of the plot, which has a lot going on. Chapter after chapter we are given what could be critical blows to both the Animorphs and to the Yeerk Peace Movement. First Ax gets sick, which affects his ability to morph. Then they discover Aftran (who started the Peace Movement) is slated to be tortured. Now they have to perform surgery on Ax within the next 24 to 48 hours and, in that same time frame, find a way into the Yeerk pool to save Aftran. Oh, and of course the rest of the Animorphs *also* capture Ax's sickness and are down for the count for both missions.

So much tension is built in this story with how high the stakes are, which already sets this book up to be one of the best in the series. However, how these two plot threads are wrapped up is possibly one of the most satisfying conclusions we see in the entire series, only to be followed up by what I think is the best closing chapter we've seen thusfar in the series. Yes, I did cry :,)

"Sometimes we do win. This time? This time, Cassie, *you* won."
40 reviews
January 21, 2023
This one is from Cassie's point of view.



I liked this one a lot, because we see the effects of and all the implications that entails. It proves her right. It proves, that kindness is ultimately always the better choice. And that you cannot put every individual in the same pot as all the other members of their race.
Profile Image for Jamie.
1,569 reviews1,242 followers
June 19, 2025
Alright so 3.5 stars is closer to accurate. But I listened to the audiobook and didn't care for the narration so down a star it goes. I felt this book had some thrilling moments, especially in the yeerk pool and how much Cassie relies on certain yeerks for help. Yet the narrator did not bring those exciting moments out very well. At times I swear she thought she was reading a text book or something -droning. Granted she did try at times but overall, blah. This book brings into play several ethical dilemmas. Cassie has some tough choices to make and not everyone will like them. Overall I liked it. Honestly though I feel being n Cassie's head is my leave favorite POV of the series.
94 reviews7 followers
March 3, 2025
Still haven’t found a Cassie book that I can really say I liked.
This one was a bit too far-fetched for me, especially the “brain surgery”.
And once again, Cassie makes incredibly foolish decisions that just *somehow happen* to work out.
There are just so many problems with the plot in this one that I don’t even feel like getting into it.
And I felt like there should’ve been more weight or reflection in this story With one of the Animorphs morphing a yeerk for the first time.
It had a few fun moments, But not one I would read again.
This entire review has been hidden because of spoilers.
Profile Image for Cat.
340 reviews1 follower
April 9, 2023
Ok I read this book a few months ago, and I remember it being wild.

We see the return of Aftran, finally, since she was first shown in the first book. We see how scary it is for a Yerk to be in Ax's brain, or how the peaceful yerks can help out. My one gripe with this book, was how they trapped Aftran in a whale morph at the end. I feel like they should have trapped her in a bird, she LOVED flying so much in the last book she was in. Idk, it's minor.
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