The Secrets of Underhill

by Kali Wallace

An 11-year-old arborist's apprentice fights to save an ancient grove of magical trees that hold the key to her community’s survival.

This immersive fantasy adventure combines vivid world-building with timely themes of environmentalism is perfect for middle grade readers of Kelly Barnhill and Jessica Townsend.

Nick Sixsmith has spent her whole life on the road. The daughter of a traveling arborist, she and her mother move from town to town, caring for the ironwood groves the communities rely upon. When a dangerous blight takes hold of these magical trees, they must journey to the city of Mistwood—her mother’s hometown—for answers.

Nick can’t wait to explore the prosperous city of Mistwood and all it has to the bustling markets and workshops, neighborhoods built under a roaring waterfall, and the vast ancestral grove of ironwood trees. But dark secrets simmer beneath the surface as people start to disappear, and tensions rise in the city. 

As the mystery grows, Nick and her new friends must follow the trail where it leads underground, to a strange, enchanting world called Underhill. Only then, among the roots of ancestral grove, will Nick find a way to save her new home and the ironwood trees.

Riveting and atmospheric, readers will be immersed until the final page.

Genres: Middle Grade, Fantasy, Nature, Adventure, Childrens

320 pages, Hardcover

First published January 28, 2025

About the author

Kali Wallace studied geology and geophysics before she decided she enjoyed inventing imaginary worlds as much as she liked researching the real one. Her short fiction has appeared in Clarkesworld, F&SF, Asimov's, Lightspeed Magazine, and Tor.com. She is the author of the dark, fantastical teen novels Shallow Graves (2016) and The Memory Trees (2017), as well as the middle grade fantasy adventure City of Islands (2018). Her first novel for adults, the sci fi horror SALVATION DAY, is forthcoming from Berkley. She lives in southern California.

Reviews

[Skye Elder · Rating 5 out of 5]

I really love this book!❤️

This fantasy book was intriguing and plot twisting.

I just have one question: what type of dog is needlenose?

[Annemieke / A Dance with Books · Rating 4 out of 5]

Thank you to Quirk Books and Netgalley for the review copy in exchange for an honest review. This does not change my opinion in anyway.

With a cover so lovely and it being a middle grade, I had to give this middle grade fantasy a try. I'm glad I did.

We meet Nick and her mother Theo as they are helping out a town with the blight in their grove. Their world uses the magic of ironwood trees but within the last two years the trees have been affected by something. It makes the magic lash out to the nature around them. To try and solve this blight they have to got to Mistwood where Theo's history lays.

There was a lot to be loved in this story. The relationship between Theo and Nick was interesting to see. It has always been just them (with the exception of a not blood related aunt). Meeting her family for the first time in Mistwood was quite the change for her. It creates an interesting dynamic. The friendship that evolves between Nick and Oliver, her cousin, is cute to see and I think something that Nick needed. Someone of her own age. I also liked seeing Oliver's older sister step up nearing the end the way that she did.

I also liked the world. Seeing the magic of the Ironwood trees and how the world is using it for everything. It kind of made me think about our dependance on certain things. And how we sometimes don't want to listen to the people who have been telling for many years how bad it was for the environment. The ending was also realistic in the way that there wasn't an easy fix, but something that the adults are still working on.

Having said that, I felt like I was missing a large piece of Nick's and Theo's background. Theo left Mystwood 15 years ago or so. Nick is 11 so she must have met Nick's dad somewhere. There has only been a mention of dad in the book and that was a mention that she doesnt know him. There is no explanation on this. The reasons for Theo's leaving and not coming back to visit her family are also a little flimsy. I found it hard to take it at face value.

But this is also a middle grade. I don't think for the target group this will be a problem per se. It is a well crafted story with likeable characters.

[Wini Fara · Rating 3 out of 5]

Unique world building, but kind of boring. Characters were whatever, even though they were the main focus of the story. This book felt like it was trying too hard to be PC.

[Renee Godding · Rating 3 out of 5]

3/5 stars

The Story:
Nick and her mother Theo are traveling arborists, moving from town to town to protect and care for the magical plants that the local community rely upon for a living. When their travels bring them to her mother’s hometown of Mistwood, they discover that a mysterious blight has been afflicting the Ironwood trees, which threatens not only the livelihoods, but the safety of large parts of the town. Alongside her cousin Oliver and their friend Lizard, who lives in Underhill - the poorest and hardest hit part of town- Nick sets out to get to the bottom of the mystery of the blight, getting involved in more than she bargained for…

What I loved:
It’s not hard to get me hyped for a cozy-middle grade adventure in a world with botanical magic. The Secrets of Underhill delivers just that. The world is beautiful and vivid and I loved how the author introduced themes of environmentalism and eco-consciousness through it, in a way that would make sense for young readers. Kali Wallace is a star at creating atmosphere; for more evidence look no further than City of Islands or The Memory Trees.
The characters are alright; I loved the friendship between Oliver and Nick, and the bravery shown by Lizard. I also really enjoyed that Nick’s mother Theo plays an active and supportive role in the story, rather than being the standard “absent parent” in coming of age tales.
And don’t get me started on the (magical?) dog character… Any inclusion of a cool dog-side character is a win in my book, both as a kid as well as as an adult.

What I didn’t love:
My favourite middle-grade novels have the power to transcend their age demographic, to where both children and adults can gain something from the story. This makes them so magical, when read together with your child. The Secrets of Underhill, although a fun story for kids up to I’d say about 10 or11, does little for older readers. The plot is very surface-level and it only truly introduces themes, rather than actually explore them. We have a strong environmentalist message, with a money-hungry company overmining natural resources, and it affecting the local community (specifically the less wealthy demographics). Yet this never moves beyond anything more than “cutting trees = bad”.
Similarly, there’s a character who uses they/them pronouns, yet not a word is actually spoken about their gender-identity or what this means to them. To an adult reader, the inclusion of these themes without actually addressing any of them in more depth may come across as performative.
On a story-telling level, I was disappointed with the final act. The resolution of the final problem simply felt too easy for the enormous stakes they were up against. Then, in the aftermath, a weighty choice is introduced to Nick, which could’ve been a powerful moment. Yet the way this is resolved felt like a cop out. Nick is given a choice between continuing to travel with her mum as an apprentice arborist, or stay in Mistwood to settle and go to regular school and have regular stable friends. This is an incredibly big choice for her, addressing a conflict that has been introduced from the start. Except, she doesn’t really chose either: she tells her mother that she wants to continue traveling with her, but álso come back regularly to Mistwood so she can keep her friends etc. This just felt like the author telling kids: you don’t ever need to make hard choices, you can have your cake and eat it too. . This last gripe could’ve just been a me-thing though…

Overall, an enjoyable read, but not a favourite for the ages. I’m absolutely watching out for whatever Kali Wallace writes next.

[Larissa]

Overall, I enjoyed this book, however I don’t know that it has a start that will just grab readers and encourage them to keep reading. I love the diversity and inclusion that this book tries to promote. And teaching kids that just because something is different doesn’t mean it should be something you fear but instead encourages kids to learn about and maybe embrace. I also like how it talks about nature and how what happens in one place can cause a ripple effect to other areas throughout the world. There is a lot of positive about this book, the ending is great. I just am not sure how many kids will get drawn in.
Thank you to Quirk Books and Netgalley for allowing me to read an advance copy of this book.

[Jennifer · Rating 3 out of 5]

This started as a cute mother/daughter traveling together and investigating magic tree related problems story, and quickly upgraded to them dealing with rampant corporate and political greed and environmental damage in a well described fantasy setting.

A quote I liked: "It was unsettling to realize that changes in places she couldn't see could throw the entire place out of balance. It was even worse to know that it had already begun, and the people who wanted to fix it had been stopped by those who refused to see that anything was wrong."

I recommend this book. :)

[Kathy MacMillan · Rating 5 out of 5]

Another instant-classic middle grade fantasy from Kali Wallace. As in her previous middle grade novels Hunters of the Lost City and City of Islands, Wallace creates a world here that feels both timeless and utterly of its own moment, filled with achingly detailed characters confronting the challenges of their own time and yet providing insight on issues plaguing our modern world. In The Secrets of Underhill, the focus is on how people coexist with their environment, and what happens when greed outweighs human lives. As Nick helps her mother explore the cause of the mysterious blight affecting magical ironwood groves everywhere, she also confronts family secrets and her own fears. A bighearted story celebrating family ties, the power of nature, and the value of standing up for what’s right.

[Ember Moto · Rating 4 out of 5]

The world is great and the magic was fun. magic plants being given the focus is not something I have seen before even though I read a lot of fantasy, so that was nice and refreshing. The characters where also fun I just wish there had been a little more backstory. Thank you to Netgalley for the ARC copy.

[Marnie · Rating 4 out of 5]

The Secrets of Underhill is an interesting fantasy story. The author gives us just enough world-building without losing us to the details. We discover a new part of the world along with the protagonist, and search for answers to a magic tree-killing fungus with her. The book is suspenseful and mysterious without being too scary - just right for early middle-year novels. I enjoyed this book and will recommend it to my students. .
Thanks to Netgalley for the ARC!

[Elise · Rating 4 out of 5]

Thank you to Netgalley for the free e-arc!

Reviewing this book proved very difficult for me. On the one hand, it had so many things I absolutely loved: plant magic, cool trees, casual LGBTQ+ rep, and a poignant metaphor for how capitalism and climate change go hand in hand. If I could rate just the core premise of this book, I'd give it a 5/5.

But the execution of the plot was really frustrating. I spent the entire first half of the book waiting for some kind of inciting incident--something that would make the larger world problems personal to Nick, something that would establish her stakes and a deadline. And it never came. Nick just kept whittling away at a mystery that was certainly important to the greater world, but without any real reason why she had to solve it, or what would go wrong if she didn't. She also lacked agency throughout the book. The plot was a lot of her reacting to other people's actions, or gaining new information and then just... going home to think about it. And when she did finally take action and gain agency toward the end of the book, another character came along and took over her whole mission! Arg! It was really frustrating.

So, yeah, I really considered rating this lower. But the plant magic, underhillers, and entire premise was wonderful, and the writing was great too. This is yet unpublished so some things might get changed/fixed before it hits the shelves!

[Cristy (Quinnbook) · Rating 4 out of 5]

One of the reasons why I love reading middle grade is the different adversities and trials our characters face and how they are able to conquer them. The Secrets of Underhill shows their reader that even if kids are facing adversities and trials, they are able to come up with valid solutions.

I enjoyed reading about our main character a lot. Nick Sixsmith is an arborist apprentice, and her mother Theo is her teacher. They are on the road a lot and that’s how Nick has been raised. Until one day a mysterious blight start causing the trees to perish and making their magic disappear. So they pack up their van filled with all sorts of critters and animals and her beloved dog to Theo’s home. There she meets family members she never knew she had and the adventure starts taking a very odd but incredible journey. I loved the aspect of kids having an apprenticeship and having vast knowledge of nature.

Especially when the towns people aren’t taking the blight seriously and fill face consequences. The atmosphere and magic system were so unique as well, I feel like after reading this book you’ll appreciate nature and the power of friendship.

[Em Jay · Rating 5 out of 5]

Lush, evocative, and bursting with adventure, THE SECRETS OF UNDERHILL is eco-fantasy at its best. I loved exploring Mistwood and Underhill alongside Nick and her friends; Kali Wallace writes setting like nobody else! There's also an excellent heaping of intrigue, humour, and heart, with a gorgeous cover to match.

Very grateful for the opportunity to read an advance copy <3

[meagreads · Rating 4 out of 5]

The Secret of Underhill was not at all what I expected it to be. At first glance, this is a tale of magic, friendship, and family. However, it’s also much more than that. The Secret of Underhill is a fantasy story that tackles themes that are relevant in today’s political climate such as the environment, discrimination and inequality. This novel blends genres, with it being both fantasy and a mystery.

I very much enjoyed my time reading this book, though it did have its flaws for me. I would give this novel a solid 3.75/5

Some of the strong points of this novel where the world building and characters. The writing of the world had an immersive feeling, and I could easily picture the beauty and magnitude of the trees and surrounding environment. The characters were charming, and I do feel like they were fully fleshed out by the end. I loved both the main character and side characters and felt as though their plot lines were authentic.
Nick as a main character felt very realistic for her age. Her flaws and “bad” choices made sense to me, and I really did appreciate going through this journey through her lens.

My main issue with this book is pacing. I really loved the first 15% of this book, I felt it properly established the characters and world, but then it kind of felt like nothing was happening for a big portion of the story (from like the 15%-50% mark). We mostly wandered around the world, and were introduced to a slight mystery but nothing truly pushed me to keep going plot and pacing wise. However, the latter half of the book did pick up, and it was much more enjoyable from that point on. I will say this book is most impactful for its discussions on the environment and racism, but not necessarily the actual storyline.

I would recommend this for contemporary readers who are looking to get into fantasy, or readers who enjoy stories with the above themes. I definitely would pick up more from this author.

Thank you to NetGalley for the ARC

[Theediscerning · Rating 2 out of 5]

Theo is a travelling arborist, and Nick her apprentice and daughter – yes, despite the names they're both female. They're forever nowadays finding problems linked with the magic ironwood groves, which have some unearthly blight and are causing issues with other wildlife as a result. When it becomes too obvious they ought to go to the capital, built around the original grove of the first, most ancient ironwoods, they do – and find things really aren't as they ought to be. No, there's bigotry, name-calling, a monopolistic company blocking off parts of the city to its residents – oh, yes, and there's definitely something connected to the magical shenanigans.

The issue is that we're here for those shenanigans, and whether we like it or not we get the worthiness and wokeness as well. The very first conversation has a pronoun-mangler in it, and that's not the only instance of such confusion on these pages. This obviously makes you doubt the focus of the author is always in the right place – and when you really struggle to get a full mental picture of the lake, river, dam, waterfall and city concerned with it all, as I did, you doubt even more.

That said, this could have been so much more worthy when it comes to its environmental message, and apart from an epilogue laying it on a bit thick, this is done much more lightly than expected. The book is clearly about misuse of natural resources, and the sort of colonialist mindset that claims some of them for some people and not for the others. Still, I don't know if this has the right balance for the young reader seeking action and drama and intrigue – there is a lot of world-building, and nothing like a key dramatic conclusion, although this is wrapped up a lot more tidily than I feared, knowing more books in this series were planned. So this gets demerits for pronoun woo-woo, and just not being a universally appealing magically-imbued fantasy, and therefore ends with two and a half stars. But it's not dreadful, and if it does still appeal I wouldn't dissuade anyone from giving it a cautious look.

[Crystal Price · Rating 3 out of 5]

It was a heartfelt story with nature and some magic, but I think the younger audience will find this very slow and somewhat boring. The PC pronoun woo woo was not necessary. Can we PLEASE leave all that out of children's books? Overall, It's a cute story about saving nature and loving your neighbors, and has a heartwarming ending.

[Ashlyn · Rating 4 out of 5]

This was a fun and quick read. I loved the passion Nick had following in her mom’s footsteps. This actually hit on some important facts of not harvesting too much at one time from the trees and how they’re all connected no matter the geographic distance. I’m glad I picked this up and would definitely check out more from this author in the future.

[Lesa Dierking]

I just couldn't finish it. I tried. I couldn't get into it.
I actually re-started it two times, thinking I would really try ... but it did not work. I might try again in the future....

[Monica Cook · Rating 4 out of 5]

The pace was a bit slow in parts, but I enjoyed this book.