Overly descriptive. Good concepts and themes but struggled to keep my attention. My full review will be published on Horrortree.com

I liked it, but I think I had high expectations going into it. Strong start that tapered a lot in the middle. Really cool plant horror though!

Very unique take on the alien invasion story. A little too long, but it was fun. More sci-fi than horror, but had plenty of traditional horror scares.

1.5/5 stars, rounded up

The concept and setup for this book was very cool, but I feel that it didn't deliver on anything promised. The themes and messaging were confusing and poorly explored. The humour made me cringe and the characters were two-dimensional, all falling into either "good" or "evil" boxes and acting in unreasonable ways. I also felt the trans rep was quite harmful, with the trans man LI only really existing to make the MC seem "good." It was a slog to read and I probably would have DNF'd if it hadn't been an ARC. Regardless, thank you to NetGalley and Tor for the eARC in exchange for my honest review.

Unfortunately this didn't work for me and I think that's more of a me problem so I'm going to give it a 3 star. I think this mostly didn't work for me because of the writing style and the strange humor peppered throughout the book. I had a big problem with figuring out the tone of the book. I absolutely love the Wayward Children's series, but the tone of those books, put into this style of book, didn't work. I was constantly trying to figure out how to feel about what was going on and it left me a little confused throughout the reading experience. I think plenty of people will really enjoy this though if they specifically really love the writing style.

I absolutely love Mira Grant, her Parasite series was one of my favourites. I love how she describes her world, the opening of this story really drew me in. When Anastasia goes into the forest and meets this flower, I absolutely loved the descriptiveness of Grant's writing and it still gives me chills. I did find that the book really slowed down coming up to the invasion. I did really enjoy how Grant delves into how people would react, though I do wish there was a little more to the invasion. She will continue to be one of my favourite authors.

Anastasia has not fit in since she walked into the forest and was turned into an alien plant. To make things worse she can't seem to help telling everyone that the alien invasion is coming. No one believes her, but they should have heeded the warning.

Science fiction and horror is a genre blend that works so well. This is a very character focused story with a quirky main character and her amazing found family. It shows the alien invasion from the perspective of an alien plant that has been raised human that needs to choose sides. It is light on horror past a very disturbing plant attack of a child, but it is an epic and fun story with an interesting perspective. If you are wanting to read about an invasion of sentient blood drinking plants that does not take itself seriously then this story is for you.

The characters jump off the page, and I enjoyed the diverse cast. Grant does an excellent job of describing the setting and making the reader feel emotion. The world-building is awesome, and I love the visual writing style. The alien world-building feels believable and immersive. There is some repetition, and it’s a slow pace, however, the last 25% was a wild ride. I laughed, I teared up, and the pages turned.

APPEAL FACTORS
Storyline: character-driven, issue-oriented, open-ended, unconventional, tragic
Pace: slow
Tone: bittersweet, dramatic, suspenseful, thought-provoking, edgy, mysterious, bleak, gruesome, violent
Humour: dark humour, offbeat, sarcastic
Writing Style: banter-filled, conversational
Character: awkward, complex, flawed, likeable, strong female, well-developed, diverse
LGBTQIA+ Representation: gay, queer, transgender
Racial Representation: Multiracial

Read Alikes:
The Scourge Between Stars by Ness Brown
Future’s Edge by Gareth Powell
Nightflyers by George R. R. Martin
Bloodmoon by Heather Graham
The War of the Worlds by H. G. Wells


› Final Thoughts
• Overgrowth is a horrific, tense, and emotional sci-fi novel about identity, found-family, and acceptance. I recommend this to readers who like plant-horror and science fiction.

Thank you to Netgalley and the publisher for a complimentary copy of this book. Opinions expressed in this review are completely my own.

A chilling sci-fi horror exploring identity, cosmic dread & fear of the unknown. It had great build up but I wanted more from the invasion part!(3.5★)

If you're looking for an alien invasion story that has no intensity, no tension, and no action for the first 50%, and is just agonizingly slow, boring, with messaging as subtle as a brick, and worst of all, repetitive, then boy do I have the story for you.

In case you were curious, the only thing that does change post-halfway point is the action. I guess that does exist. Just depends on if it suits you. Or if, after all that time, it even interests you. But it still manages to be slow, cycles through the same thought processes and considerations and situations from before, just with some other bits in the mix. Because y'know.. the invasion does happen. The plant people hiding in human skin suits start to be less human, and more plant people, and they do what they were sent to do. And there is a lot -- so much -- explaining behind the reasons for it. If you're interested. Which I was not.

But what is consistent, no matter the percentage, was the inconsistencies of characters from one paragraph to the next -- which also means this wasn't particularly well-written. Or well thought out. Maybe both. Not that the characters even had much personality to differentiate themselves. But I'll nip this in the bud (snort), I've complained enough as it is.

Considering how my adventures with this author's other series under their other pen name, notably the October Daye series which has driven me to distraction whereas the Wayward Children series is.. maybe a bit up and down but still overall enjoyable, I don't know why I took a chance on this one. Leftover love for the Newsflesh series? A general love for sci-fi? While both are valid, but I still should've known better.

Can't recommend this one, friends. Sorry. I'm just glad it's over.

1.5 stars

A young girl discovers a beautiful flower in the woods, and the incursion begins.

It feels wrong to give this book a 3, because it was a blast to read. I found myself absolutely engulfed by the story, especially within the first half. Unfortunately, the book is weighed down by an anticlimactic ending (or an overall tame story) and a lot of questionable moral statements.

The book looks at identity, otherness, and the nature of humanity. The story is about an alien species looking to spreed its seed. At the start, it reads almost like a warped wayward children story of a seedling looking for a world where they belong and are accepted. Anastasia is an alien. She tells everyone that from the start. Of course, no one believes her, but nevertheless she finds her group who accepts her.

One of the central themes in Overgrowth is the idea of accepting people as they present themselves, even when they seem strange or unbelievable. This feels like its intended to mirror the language of queer and trans allegory, and on the surface, the story seems to celebrate radical acceptance. However, I think the metaphor starts to unravel under scrutiny.

The story equates claiming to be an alien with claiming a gender identity, but that parallel feels ethically and conceptually shaky. Gender is a social construct that is fluid and culturally embedded, while species identity is a material and biological distinction. Framing gender queerness as analogous to identifying as an alien risks trivializing it, reducing it to a quirky or harmless fantasy rather than a lived reality grounded in both experience and social struggle.

More troublingly, this metaphor sidesteps the dangers of uncritical acceptance. We live in a time shaped by science denial and conspiracy theories. The idea that all claims should be accepted at face value, even fantastical or self-serving ones, can be harmful. Some beliefs and identities, especially when rooted in harmful ideologies, deserve interrogation, not affirmation. The book’s message of blanket acceptance might work as allegory, but it brushes aside the need for discernment in the real world.

I can't say this a critical failure of the book, but it is framed as a fundamental aspect of the narrative. The entire invasion is justified by the lack of acceptance of these claims of being alien in the most cringe way. The entire invasion could have been avoided the humans had just accepted what they were told as truth and told the messengers that they did not want to be invaded. As a mechanic, I don't think it fails completely, but it becomes a literal justification by our main character for why humans deserve whats coming.

It is our failure to believe people are who they say they are, even when there is absolutely no reason to believe such an extreme claim. It intersects with my original concern around the harm of critical thinking and asking what is and isn't worth believing. Imagine if the moral of this story was taken literally. What does it even mean to believe? One character is said to have decided to believe what they were told, as if belief is something we can just decide to have or not have.

I almost forgot another thing that really frustrated me: using NASA as the representative of the big bad government. Realistically, this is my smallest critique as its more personal, but I think it is a huge mischaracterization of NASA to lump it (and the astrobiologists within it) into the militant part of the government. They literally worry about a robot on Mars might disturb possible microbes. As a astrobiologist and planetary scientist, I assure you, NASA scientists would almost certainly advocate peace.

At the end of the day, I enjoyed this book, but I feel uncomfortable with some of its messaging. I also think it needed more horror and less exposition. At the very least, it was thought provoking which made for an engaging read, and for that I am grateful.

For a book about an alien invasion, there’s not a lot of aliens invading.

And then it turns out it’s the most casual alien invasion ever lol

Bummer to because that prologue was eerily creepy but it did not in fact set the stage.

3.5/5 An alien invasion from the perspective of the invading alien. Add on that the invading alien does not know the plan or if invasion day is even going to happen. This story had a very interesting take on alien invasions! If the topics of found family and self-discovery with a touch of carnivorous blood sucking plant aliens sounds like a delight then this book is for you. I really enjoyed this story but it felt very slow paced and took me 2/3 of the way through to finally get invested. But man, that ending was poetic and absolutely made it worth it.

Rounding up to 4 stars because in the end I like a lot more about it than the things that didn't work as well for me.

Overgrowth is a found family adventure story set on the eve - and during the event of - an alien invasion, one that's been warned for about thirty-some-odd years. It's Invasion of the Body Snatchers, but very queer and told from the first person point of view of one of the snatched as she has to figure out her life as literally, a plant person alien invader, even though she's been "human" as far as she could remember (which is only since about age 3 when the person she was was eaten by an alien flower and the person she is was birthed out of that).

Overgrowth is full of gorgeous descriptions of vegetation across the spectrum (I can only imagine how hard it must have been to come up with varying ways to describe plants and plant life for 400+ pages) and more deeply, the queer experience as Anastacia herself is queer, her boyfriend is trans, and the whole plant person thing can easily be an allegory for trans existence/acceptance as well - certainly Stacia pulls the similarities more that once.

And that's what doesn't quite work, either. Overgrowth could have used a lot of editing, perhaps, or just tightening up of how often certain messages were repeated. I'd LIKE TO think (though social media often proves me wrong) that readers can get a message and internalize it without having to repeat those messages so many times, but we also live in 2025 and this book takes place in 2031 and honestly although at first it was jarring to have something set so close to today's life, a lot of the points made by the invaders are not invalid and don't seem to be clearing up anytime in the next five years (here is where I would insert a melting face emoji were I typing this on a phone). The middle really did drag for me, even when things were happening, and I think a lot of it was Stacia's internal monologue and self-justification versus self-denial especially when in-story she had too much time to think.

But then again, there were a lot of interesting things! The dream forest, the psychic pollen, the visuals of the aliens, also if I may say the gore and despair because an invasion is not a fun time, not should it be! There were also a few parts that I see other reviewers didn't like (a line about pronouns later on -- vague to save from spoilers) that I actually *did* like, even if they seemed silly or out of place from the OUTSIDE I feel like they were in line with Stacia's character and/or thought process at the time when it came to trying to mesh how these plant aliens lived with how she now had to figure out what she assumed the rest of her life might be like. And let me just say, being someone who used to cosplay for 10+ years, having Stacia's bff/roommate credited constantly as "a cosplayer" besides her actual well to do job was very funny (positive) and also like, 'Yeah! We can do a lot!'

Caitlin Kelly did a *fantastic* job with the narration, bringing to life a whole cast of characters (several of whom couldn't even speak "into the air") in a way that should always be credited as a performance over just narration. I'm not someone who's always great with audiobooks (I've been trying the last few years!) so to find one with such high tier performance is always a joy!

So overall I enjoyed this book even though it took me a while to get through and the parts I'll be thinking about are the more positive parts (especially the post-invasion-start parts really) and that's all enough to slide toward the upper rounding part of this star-rating thing.

Thank you so much to Tor Nightfire for the eARC in exchange for review!

“I was an alien. I was not of this world. And one way or another, I was going to have to reconcile that with a lifetime lived among these people, who had been my friends and my family and my home.”

Thank you to NetGalley and the publisher for the eARC! This book was published in the US by Tor on May 6th, 2025.

What if you always knew you didn’t belong—but no one believed you?

In Overgrowth, Mira Grant gifts us a sci-fi horror that is part alien invasion, part existential exploration, and all heart. From the moment a comet seeds Earth with eerie, sentient flora, Grant roots her narrative in dread and wonder. What grows from those seeds—literally and metaphorically—is a richly layered story about identity, transformation, and the uneasy intimacy of being seen.

We meet Anastasia as a child warned never to enter the woods, and like all the best horror books, she does. What returns is not quite the same girl. Or maybe it is. As an adult, she goes by Stasia, living in Seattle, working tech, and still insisting she’s an alien sent to warn of an invasion. Most treat her story as trauma-induced delusion—until a broadcast arrives from the stars.

What unfolds is a slippery, haunting exploration of what it means to be human when you’ve always felt other. Stasia is a brilliant protagonist: alien in form, alienated in life, cuttingly funny and quietly grieving. Her voice is a balm for anyone who’s ever felt like an imposter in their own skin, or in their own community.

Grant’s prose blooms with strange beauty. The vines crawling beneath Stasia’s skin aren’t just body horror—they’re metaphor made flesh. Trauma and transformation are never separate here; instead, they’re intertwined like roots and memory. The novel digs deep into themes familiar to many queer and neurodivergent readers: disbelieved truths, found family, bodily autonomy, and the terrifying intimacy of letting someone care for you when you feel unknowable.

Even as the ending rushes past in a slightly-too-neat conclusion, the emotional stakes never wither. Overgrowth is less about saving humanity and more about who counts as human to begin with. And who gets to decide.

If you’ve ever been called dramatic for telling the truth—or told you were “too sensitive” when you were just right—Stasia might feel like coming home. Even if, like her, you were grown in a garden meant to devour you. Weird, wrenching, and deeply tender. Highly recommend.

📖 Read this if you love: queer sci-fi, neurodivergent-coded protagonists, slow-burning existential dread, and metaphor-rich body horror that doubles as a meditation on trauma and belonging.

🔑 Key Themes: Alienation and Identity, Difference and Disbelief, Bodily Autonomy, Found Family, Belonging Beyond Humanity.

Content / Trigger Warnings: Child Death (minor), Alcohol (minor), Transphobia (minor), Medical Content (minor), Confinement (minor), Blood (minor), Gun Violence (minor), Gore (minor), Murder (minor), Animal Death (minor).

This is a wonderful Cassandra of the alien invasion story. Aliens grow their own version if themselves on Earth and give their kids a compulsion to tell everyone the aliens are coming, but no one listens. Typical Earth people who think nothing bad will ever happen. The best part of this book is the realistic reactions of the characters to things that happen. The ending was also excellent.

i loveddd into the drowning deep and sang her praises for years. this is a close second for me!! this did not end how i thought at ALL but i loved it holyy. and becoming a plant person?? sign me up!!

4.5, rounded up

Overgrowth is a sci-fi horror novel about what it means to be human narrated by Stasia, an alien plant wearing a human skin suit. The novel, while being about an impending invasion on the surface, has a beating heart that delves into the nuances of found family, identity, human rights, and marginalization. The prose is inviting and free of frills, and the characters are diverse and eclectic. If you love descriptions of alien ships, biology, and telepathic communication, you're in for a real treat.

My only complaint refers to the repetition throughout; quite a few plot points are heavy handed in their distribution, being spelled out over a dozen times each. While this isn't an inherent issue, as the story is told from Stasia's point of view and spotlights the repetition of actual thought processes, I would have appreciated less redundancy.

If you're looking for a story akin to War of the Worlds or Little Shop of Horrors, this is for you.

I was given a free advance reader’s copy of Overgrowth by Mira Grant from Tor Nightfire via NetGalley in exchange for an honest review. Thank you, Tor Nightfire!

Mira Grant is the pseudonym used by Seanan McGuire when she writes horror or horror-leaning books and stories. This is the first Mira Grant book I’ve read, although I own Feed, and I’ve been meaning to read it and the Newsflesh series. If Overgrowth is a good representation of her horror work, then I definitely need to bump those books up closer to the top of my TBR. I really enjoyed reading this book, but there’s a lot to unpack here, so get ready. Ready? Ok, here we go.

Overgrowth takes place on a near-future Earth, mostly in the year 2031, and it follows a woman named Anastasia Miller. Stasia, as her friends call her, has an unusual history. At the age of 3, she wandered into the woods behind her house, disappeared for three days, and suddenly reappeared in her grandmother’s kitchen. She was scratched and a bit ruffled, but seemed to be otherwise unharmed. Until she began to insist she wasn’t really Anastasia. Instead, she said she was really an alien plant person and a harbinger of an upcoming invasion of the planet.

Naturally, Stasia’s mother and grandparents and everyone else involved believed the trauma of her kidnapping must have induced this admittedly strange coping mechanism in which Stasia has created a fantasy world for herself to explain where she’s been. As the years go on, though, Stasia’s story stays the same. No matter how many therapy sessions, MRI’s, anti-psychotics, and other treatments she undergoes over the next 30 years, Stasia still firmly insists she is an alien.

This obviously leads to a troubled upbringing. Stasia has a lot of difficulty making and keeping friends, and she endures endless bullying at school. Children can be cruel at the best of times, but anytime someone is different, it’s like that person is carrying a homing beacon for the cruelty of others. Stasia became a target of bullying, and even her teachers began to express concern for her. This continues into adulthood, at her job, in her home with her roommates. Even the friends she’s able to make don’t truly believe what Stasia is saying.

The way this difference is handled over the course of the story, though, makes it obvious that this is a metaphor for neurodivergence. Stasia has a lot of trouble feeling human. She knows she’s different, and she knows she’s not human. But, all of the treatments and therapy have sort of gaslighted her into doubting herself. Like many neurodivergent people, she has come up with rules to abide by when interacting with others and trying to live in the world.

In spite of this difficulty, at the time of the events in the book, Stasia has been in a stable romantic relationship for the past ten years with a trans man named Graham. This was another part of the story that I really enjoyed. Stasia has a moment of reminiscence about her and Graham’s early relationship and the difficulties of being in an LGBTQ relationship. I feel like a lot of people will be able to identify with their early struggles and their insistence on continuing to love each other.

In fact, choice is a big running theme throughout the story. Stasia constantly chooses Graham and her friends when she could easily choose her own people. She struggles with making human or alien choices. When the time comes, and it turns out that Stasia has been telling the truth all along about her origins, Graham and her friends have to decide if staying with Stasia is worth staying alive. There’s a very poignant discussion between Stasia, Graham, and her friends at one point that really illustrated this.

Anastasia Miller did not walk back out of those woods after missing for three days. In the opening portion of the book, the reader knows what no one else besides Stasia knows. Anastasia Miller was consumed by an alien plant, replicated, and released to walk among humanity until the time was right for the invasion. When Graham and Stasia’s friends find out she essentially ate a three year old, they are rightly shocked and disgusted. Nothing else up to this point in the story had truly emphasized Stasia’s alien nature to them, and they had to make a hard choice: stay with Stasia and maybe stay alive, or side with humanity and die.

However, Stasia wasn’t given a choice. Her seed was deposited on Earth, and the flower that sprouted from it chose for her. There are many points in the book that Stasia’s choices are made for her. The entire invasion happens because her species was faced with a choice: invade other worlds to survive or die. It is the desire of all life to sustain itself, and all sentient beings want to live and remain sentient.

I truly enjoyed the ending of this book, but I will not give it away. I just really liked how Mira Grant managed to instill this constant tension while reading. All alien invasion stories inevitably posit the question “Will humanity prevail?” This book definitely answers that question.

I gave Overgrowth by Mira Grant four out of five stars. This book was such an interesting exploration of the concept of alien invasions as told from the perspective of one of the invaders. I think that’s pretty unique in the sub-genre. Stasia is a well executed character with depth, and I really cared about what happened to her. Her inner struggles were the highlight of the story, but it didn’t leave as much room as I would’ve liked for more development in the side characters. Regardless, if you’re looking for sci-fi horror with a dash of existential dread definitely give this book a read!

I don’t read a ton of sci-fi, and pretty much no alien prose, but I has a blast with Overgrowth. The lead-up to the invasion is tense and mysterious, and the actual invasion challenges all your assumptions. I may have cheered for the alien invaders at times.

The story itself is great, but the framing device really knocks it out of the park.