Sea Otter Sunrise

Magic Tree House #40

by Mary Pope Osborne, A.G. Ford (illustrator)

The #1 bestselling Magic Tree House series for chapter book readers is ready to whisk you away across the world with Jack and Annie--this time to save sea otters after a shark attack! Magic Tree House is the perfect series for kids ready to transition from leveled readers and picture books to longer novels!

It’s bright and early when the magic tree house spins Jack and Annie to Monterey Bay, California. It’s their mission to collect sea urchins in the underwater kelp forests! But they know nothing about collecting sea urchins—can a grouchy boat captain help them? Maybe. But Jack and Annie have another problem when Annie finds a badly injured sea otter. They’re not supposed to help the otter . . . but it’s the right thing to do. Can they convince the grouchy boat captain to help them?  

Did you know that there's a Magic Tree House book for every kid?
Magic Tree Perfect for readers who are just beginning chapter booksMerlin More challenging adventures for the experienced readerFact Nonfiction companions to your favorite Magic Tree House adventuresGraphic Relive the original adventures brought to life with art by Kelly & Nichole Matthews
If you're looking for Merlin Mission #40: Eve of the Emperor Penguin, it was renumbered as Merlin Mission #12 when the series was rebranded in 2017.

Genres: Fantasy, Childrens, Chapter Books, Young Adult, Adventure, Audiobook, Animals

94 pages, Kindle Edition

First published July 1, 2025

About the author

Mary Pope Osborne is an American author of children's books and audiobook narrator. She is best known as the author of the Magic Tree House series, which as of 2017 sold more than 134 million copies worldwide. Both the series and Osborne have won awards, including for Osborne's charitable efforts at promoting children's literacy. One of four children, Osborne moved around in her childhood before attending the University of North Carolina. Following college, Osborne traveled before moving to New York City. She somewhat spontaneously began to write, and her first book was published in 1982. She went on to write a variety of other children's and young adult books before starting the Magic Tree House series in 1992. Osborne's sister Natalie Pope Boyce has written several compendium books to the Magic Tree House series, sometimes with Osborne's husband Will Osborne.

Reviews

[Angela Hull]

Okay this book is a five star for me simply for the fact that the offers were so cute. I love the fact that Bob’s whole demeanor changed after meeting the otters

[Hope Anderson (HopelessBookAddict)]

Legit might be in my top 5 for this series! SO cute!

[Opal]

This is standing in for having finished all 40 of the currently published books in the regular Magic Tree House series, which feels like a proper accomplishment worthy of being marked here. I have been reading them out loud to my little sister for the past 6 months or so. Now we start the Merlin Missions!

[Mystic DreamClouds]

Review to follow soon...

[Riley Lewis]

My boys and I were excited about a new Magic Treehouse book and that is about one of our favorite animals. We liked it but maybe a simpler plot than some of the other books in the series.

Here is a summary for my records:
Jack and Annie are sent to Monterey Bay, California, where they have a mission to collect sea urchins from underwater kelp forests. Neither of them knows much about scuba diving or sea urchins, so they end up working with a grumpy boat captain named Bob. My boys loved Bobs boat.

While diving, Annie discovers a sea otter that has been badly injured after a shark attack. Their instructions are to focus on their mission and not interfere, but Annie feels they can’t simply leave the animal suffering. Jack agrees, and they try to convince Captain Bob to help rescue it.

At first, Bob resists. However, Jack and Annie’s concern for the otter gradually softens him. Together they work to get the injured otter help. The children learn about the delicate balance of the Monterey Bay ecosystem. They discover that sea otters play a crucial role by eating sea urchins, which helps protect the kelp forests.

The sea otter is successfully rescued and receives care. Bob’s attitude changes as he sees the importance of protecting wildlife, and Jack and Annie complete their mission before returning home in the Magic Tree House. The book ends on an uplifting note about compassion, conservation, and doing the right thing even when it is inconvenient.

[Rachael Brothers]

I’m conflicted about this book. Being very familiar with the area and the aquarium this story was off in so many places. Mainly though there is a Marine Mammal Center number that people should call to get help for an injured sea mammal. 415-289-7325 I think it would have been a better story if the characters shared what should actually be done in this situation (yeah I get the main characters don’t have cell phones but it would be consistent with the story line to have another character with a phone or radio) I have a hard time believing the MBA had anything to do with this story. It’s great the author is writing stories about endangered animals but in this case I think it was presented poorly.

[Dean]

2.5 stars - A slightly below-average entry into the series. In general, the animal-focused stories aren't my favorite. I prefer the more historical or fantastical ones, but I'm sure kids who love animals will thoroughly enjoy it.

One note though - In the earlier stories, Jack was an overly cautious know-it-all, while Annie was impetuous, with a magical connection to animals. It created a nice balance with each contributing to the adventures. As more and more stories have focused on animals, Annie has become the know-it-all, and Jack's role has diminished. He has become almost superfluous, which, to me, undermines the dynamic balance these stories had.

[Olivia Spring]

Can’t believe we finished the series! Long wait at the library for this last one but we managed to finish the original series without buying a book, yay!

This was pretty cute and I loved the grumpy sailor being won over by the sea otter mom and baby. Not my favorite MTH but pretty sweet.

The original 28 are still my favorite and especially 24-28! I wish she hadn’t modernized the last 12 because the occcasional references to YouTube etc. were strange to me knowing that Jack and Annie were supposedly born in the 80s.

Might have to start over at the beginning soon. :)

[Roy Meyer]

After reading 68 other Magic Tree House books I didn’t really expect Osborne could do another book as well, yet she did - and this one is a true masterpiece, one of the best in the whole series. My kid was open-mouthed with awe at the descriptions of the ocean ecosystem, and crying with laughter at the later scenes with Captain Bob. Join Jack and Annie again as they go to save sea otters in California and deal with a grouchy sea captain.

[Hilary Ritchie]

Who gave these children magical scuba suits and access to marine wildlife?! Never touch a wild animal if you can help it, especially if world-renowned marine biologists are just around the bay! Annie was totally in the wrong here and I hope there's a deleted scene where Michelle chews out Annie for thinking she, a seven-year-old child could remove an animal from its habitat without an adult present. We do love to see Bob's growth over the course of the book. That's the true magic.

[Jackie]

I've finally finished this cherished childhood series. It was very weird when Jack and Annie mentioned YouTube. I loved how this book acknowledged the struggle between letting nature carry out its course, but also helping endangered beings. I'm also a huge fan of otters, so this book brought me a lot of joy. Good job, Jack and Annie, and I hope your Merlin Missions bring more adventure into your lives.

[Cherish Brown]

(4☆ Would recommend)
I learned about this series from my 6-year-old son. He loves these books. I liked how the books aren't super long, so emergent readers & younger kids can enjoy them. I liked how the personalities of Jack & Annie are so different. I really enjoyed how the story encompasses friendship. Would recommend.

[Denise]

And with this my children and I have read the Magic Tree House main Series. Next up, Merlin Missions, starting with the ones renumbered in 2017.

Love how much conservation was taught in the most recently published books, including asea Otter Sunrise. It was fun reading Bob's dialogue outlook, considering he almost entirely spoke in all caps.

[Shauna Morrison]

I miss reading these stories with my daughter, unfortunately, she is now an adult and it would be awkward reading these together now. :)
This was a fun story with Jack and Annie saving some otters and helping a sea captain lose his grouchiness.

[Clara Evelyn]

This was a wonderful read-aloud with my 7-year-old. The story not only entertained but also introduced valuable lessons about compassion, responsibility, and marine life. It sparked curiosity, and we ended up looking up more facts about sea otters and kelp forests afterward.

[leirasreads]

This was soooo cute! I loved that Jack and Annie’s adventure took place in Monterey Bay, California. This series is so educational for young readers (highly recommend) and is a nostalgic read for me.

I think this would be Travis Kelce approved since we know he loves sea otters!

[PottWab Regional Library]

SM

[Sarah]

3.5

[Andrew Heitland]

When I saw this book at the library, I instantly thought of 5 year old Andrew! And to top it off, my fav animals are sea otters! This book was super fun and awesome!

[➳ Anthony ➳]

I forgot how short these were. A good read.

[Laura]

Cute short story with sea otters teaching how caring for animals changes people for the better.

My 9 year old and I listened as we ran errands and it was a hit.

[Laura]

Loved being with Jack and Annie on another adventure!

[Tonia Eason]

I think this is my favorite magic treehouse book so far. Otters are a favorite animal of mine. It's a cute story with lots of facts.

[Mara M]

travis kelce would approve

[Katy Lovejoy]

im glad I decided to read all the books in this series finally

[Mary T]

I read this back and forth with my 7yo son. We weren't super into it but finished it. It didn't seem as good as some of the earlier ones in the series.

[Olivia phillips]

I loved it! Otters are my fave!

[Devorah]

I liked the part where they saved Sunrise and Bobby from dying, those are the two otters on the cover.

[Christine]

When i read an entire book aloud during vacation, it gets count as read.
Whole family enjoyed the sea otter.

[Jasmine Galloway]

I made it through this series!!! This was a cute reread and these books are so good! They held up phenomenally.