What Stalks the Deep

I have a very simple personal policy when it comes to abandoned mines: absolutely not.

I don’t crawl.
I don’t squeeze.
I don’t descend into the earth like a curious Victorian orphan with a lantern and poor impulse control.

So naturally, I read What Stalks the Deep by T. Kingfisher, the third novella in the Sworn Soldier series, in which our long-suffering protagonist Alex Easton travels to America to investigate a haunted coal mine in West Virginia. Against their will. For friendship.

This series has become Kingfisher’s ongoing experiment in cozy horror, and at this point the formula is clear: take something objectively horrifying, add dry humor, emotionally reserved characters, themes of trauma and belonging, and then gently sand down the sharpest edges so the story doesn’t actually bite you. If What Moves the Dead was nature horror with teeth, What Stalks the Deep is underground weird fiction with a reassuring hand on your shoulder.

Alex Easton, retired Gallacian soldier and professional magnet for the unnatural, is summoned by Dr. Denton, an old friend from book one. Denton’s cousin Oscar has gone missing after exploring a family-owned coal mine. Letters turned strange. Sounds turned wet. Lights appeared where light should not exist. You know, normal mine things. Easton arrives with their ever-unflappable companion Angus, and together with Denton and a few new faces, they head underground.

The setting is easily the strongest part of the book. Kingfisher excels at atmosphere, and the mine feels oppressive, dark, and unwelcoming in that deeply personal way only enclosed spaces can manage. You feel the rock overhead. You feel the lack of air. You feel the growing sense that the earth is not designed with human comfort in mind. If you are claustrophobic, this book knows it, and it smiles quietly to itself.

Easton remains a joy to read. Their narration is dry, observant, and faintly allergic to emotional introspection. They are brave without being flashy, sarcastic without being cruel, and deeply uncomfortable with vulnerability, which makes the quieter character moments land well. There’s a little more emotional development here than in What Feasts at Night, particularly in Easton’s relationship with Denton, and I appreciated that the book allows those moments to exist without overexplaining them.

Kingfisher’s humor is still doing a lot of heavy lifting. The banter works, the internal monologue is sharp, and the cultural observations of America through Easton’s Gallacian lens are amusing without turning mean-spirited. This is a writer very comfortable with her voice, and it shows.

That said, this is where my enthusiasm starts to taper.

Despite the strong setup and eerie atmosphere, What Stalks the Deep is the least frightening entry in the series so far. The build-up promises dread, but once the central mystery is revealed, the tension drains away faster than water through a cracked tunnel. The story shifts from ominous to oddly gentle, and while I understand what Kingfisher is doing thematically, it left me wanting more bite.

The antagonist, such as it is, is interesting in concept but not particularly threatening in execution. At times, it felt less like a horror reveal and more like a philosophical conversation held underground with poor lighting. There is a point where the monster becomes almost… charming? Which is impressive in its own way, but also not what I was hoping for when I signed up for haunted mine horror.

There’s also a noticeable repetition of Easton’s favored exclamation (“Christ’s blood!”) that became distracting. Not offensive, just overused to the point where I started noticing it instead of the moment it was meant to heighten.

Another minor gripe: Easton feels more reactive than proactive in this installment. They observe, comment, and endure admirably, but much of the problem-solving happens around them. It’s not a dealbreaker, but it did make the story feel slightly less dynamic than the first novella.

All that said, I didn’t dislike this book. I enjoyed it. I read it quickly. I will almost certainly read the next one. Kingfisher’s ability to blend horror, humor, and compassion remains unmatched, and even when a story doesn’t fully land for me, I still appreciate the craftsmanship behind it.

What Stalks the Deep is cozy weird fiction masquerading as horror. It’s a campfire story told underground, more interested in connection than terror. If you’re looking for relentless dread, this may feel soft. If you enjoy thoughtful, slightly unsettling stories with heart, you’ll likely have a good time.

3.75 stars, rounded up because Alex Easton continues to be a protagonist worth following, and because I clearly enjoy complaining about books I plan to keep reading anyway.

I’d picked up the first Sworn Soldier novella as a discounted purchase at the register at a book store coffee shop. The cover art was intriguing and it seemed… short. I was enchanted almost immediately but the characters and the balance of horror and humor. The series has only gotten better and this latest story is my favorite yet. The “monster” here is surprising and, along with the change of setting, keeps the ongoing story of Alex and the gang fresh and interesting. I hope the author continues to find inspiration and continues this charming series.

If the first in the series is a tragic first contact book, this is... well, a bit less tragic and also not first contact and also there were some scary bits. Caves. You know stuff is in them.