Book Review: “What Stalks the Deep” by T. Kingfisher

Aug 10

Håfa adai and welcome to spooky season, my favorite month of the year! Throughout October 2025, I will publish reviews for works of horror, suspense, and the supernatural. My fourth spooky pick for the month is What Stalks the Deep, the third book of the Sworn Soldier series by T. Kingfisher.

This book review consists of two parts: a spoiler-free plot summary and my thoughts on the story. In the second part, I give my personal rating and break down the setting and worldbuilding, storytelling, cast of characters, and themes. There may be some lightweight spoilers—such as how characters interact with each other and the world around them—but I will not give away any major plot twists or endings. I want to share my opinions of the book and maybe encourage you to purchase a copy of your own.

Click on the tags at the bottom of this post to see all reviews with the same tags in the Horror bookshelf.

Spoiler-Free Plot Summary

The American medical doctor James Denton has become a true friend to retired sworn soldier Alex Easton. It was only two years ago when they met in Ruravia, at the crumbling mansion of her dying childhood friend, Madeline Usher. It was only two years ago that they faced and defeated a malicious mycelium entity intent on taking over all life around it. So, when the doctor sent an urgent letter requesting that Alex Easton and Angus travel to America, they did just that. It helped that the doctor had included two tickets to Boston, Massachusetts with his letter.

So, with Hob boarded in a Parisian stable, Alex Easton and Angus travel to Boston to help Denton find his missing cousin Oscar. Denton received cryptic letters from Oscar about observations in the coal mines of West Virginia, of red lights in the dark where there should be no illumination at all, followed by a last letter telling Denton to ignore all previous letters and not to come at all. He has not seen or heard from his cousin since. To Alex Easton, something is oddly familiar, but also unsettlingly alien, about this entire situation.

My Thoughts on What Stalks the Deep: 5 stars!

In What Stalks the Deep, T. Kingfisher takes the Sworn Soldier Series in a new direction by changing the setting to North America and—from my interpretation—incorporating influence from John Carpenter’s classic 1982 science fiction film The Thing. This lends to the characters’ intense feelings of claustrophobia conveyed throughout the story taking shape in more ways than one. There is, of course, the intently uncomfortable notion of spending time in and around an abandoned coal mine. And then there is the unsettling notion that someone is not who, or what, they appear to be.

What Stalks the Deep takes place in West Virginia, two years after the events of What Moves the Dead, one year after What Feasts at Night, and in the aftermath of the Spanish-American War. The main set of characters featured in this installment includes Alex Easton, Angus, James Denton, and Denton’s acquaintance John Ingold. Following the first-person perspective of Alex Easton, as is the case with the previous two installations in this series, What Stalks the Deep explores themes of loneliness, identities of pain, colonial notions of wholeness, and how trauma can take away your ability to go home.

Without going into too much detail about any of these points, the first theme that stood out to me is what an individual might be driven to do when surrounded by the pain of loneliness. Throughout the story, an individual who became separated from their main community (for lack of a better description) used an intense form of manipulation to ensure they would not be separated again. The second theme that caught my attention is the problem that arises when someone makes pain a part of their identity. There is a line said in the first few minutes of Chapter 14 that reflects this and resonates deeply with me: “Sometimes, when people hurt for a long time, they start to think that hurting is part of who they are. And then, anything that helps the hurt, even healing, feels like it’s trying to strip part of them away.”

The third theme that became apparent to me in the story is the colonial notion of wholeness. A line said in Chapter 15 reflects this: “Their record of things that are not… part of their wholeness, isn’t good.” Said in reference to the United States’ recent acquisition of Guam as a colony, this also applies to specific individuals in the story. I truly appreciate this acknowledgement. Yes, it is “telling” instead of “showing.” But there are so few works of literature that I have encountered that explicitly state this. The fourth theme that stood out to me is how the effects of trauma mean a person can never truly return home. In this story, it is especially true for Dr. James Denton. His horrifying war experiences, coupled with what he goes through here, add an extra level of tragedy to his individual story.

My overall rating for What Stalks the Deep is 5 out of 5 stars! I pre-ordered my copy of this book earlier this year, and I could not wait to experience it. T. Kingfisher adds a creepy science fiction twist to her gothic horror Sworn Soldier Series in this third installation. As usual, her writing is emotional, funny, witty, insightful, and vivid. I will admit that I am easily excited whenever any literature or media mentions my home island of Guam. And T. Kingfisher mentions Guam nine times throughout the book! I really enjoy the entire Sworn Soldier series. I have revisited the first and second books in the series multiple times now, and I can see myself doing the same with this third book. I highly recommend What Stalks the Deep to fans of low-intensity gothic horror with hints of popular sci-fi influence.

Dångkulo' na' saina ma'åse'! Thank you so much for reading my review of What Stalks the Deep by T. Kingfisher.

Rating Cheat Sheet

4.75 - 5.00 stars: Everyone should read this book! (If you’re into that sort of thing.)
4.00 - 4.50 stars: I appreciated many aspects of this book. I recommend it!
3.00 - 3.75 stars: I liked some aspects of this book. I won’t revisit it, but someone else might really like it.
2.00 - 2.75 stars: There were some things I appreciated about this book, but I do not recommend it.
0.25 - 1.75 stars: I do not recommend this book. I did not enjoy or appreciate the experience of it.

Post Date: 28 October 2025