What Stalks the Deep by T. Kingfisher – Review

Published: September 30, 2025

Publisher: Tor Nightfire

Series: Sworn Soldier #3

Genre: Horror

Pages: 192 (Kindle)

My Rating: 4 Stars

A copy of this book was provided by the publisher in exchange for an honest review.

Synopsis:
The next installment in the New York Times bestselling Sworn Soldier series, featuring Alex Easton investigating the dark, mysterious depths of a coal mine in America.

Alex Easton does not want to visit America.

They particularly do not want to visit an abandoned coal mine in West Virginia with a reputation for being haunted.

But when their old friend Dr. Denton summons them to help find his lost cousin—who went missing in that very mine—well, sometimes a sworn soldier has to do what a sworn soldier has to do…

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I got a very last minute approval for What Stalks the Deep on NetGalley and was delighted! I immediately picked it up with the intention to just read a few pages and see how much it grabbed my attention in the first few pages. Well, next thing I knew, I was halfway through the book!

What Stalks the Deep follows Alex Easton and Angus to the United States, specifically West Virginia, where they are helping out an old friend with a situation. A possibly supernatural situation. You see, Dr. Denton was there at the Usher house and knew Alex and Angus would first of all, believe him and second of all, help with the uncanny. This is a short book and most of the fun is unraveling the unknown so I won’t go into much detail and this will be a teensy little review.

I think this installment does the creep factor well and I like the overall feel of this story better than What Feasts at Night. Nothing says creepy like exploring an abandoned mine, in search of a missing man and not knowing exactly what may have happened to him. Even without the supernatural a mine is a dangerous, terrifying place! Add in that factor and the suspense and terror of the dark gets cranked up several notches. The only reason I read this book in two sittings rather than one is because I got creeped out late at night and decided the rest of the story was better left for daylight hours!

Overall, I enjoyed a return to the Sworn Soldier series and thought this was a step above the previous installment which had left me somewhat disappointed. What Stalks the Deep ended in such a way that I suspect Alex and Angus will be doing some more dangerous things in America and I look forward to where this goes next. As always, T. Kingfisher does a fantastic job balancing a bit of horror with her unique sense of humor. I think this particular series of novellas is a great way to try out her horror-leaning works to see if you may enjoy them.