The Terrarium/Katie Collom
Bantam/November 10, 2026
Annie, our narrator Katie Collom’s The Terrarium, is a mid-thirties underachiever barely making ends meet between cat-sitting gigs and slinging lattes at The Jumping Bean. She has no car because she can’t afford one, seemingly no close friends, and a minor bout of kleptomania.
When a new client, Zoe, reaches out to book Annie to watch her majestic Main Coon, Hades, the request comes in the nick of time. Due to a misunderstanding at another client’s house, an ancient cat is dead; and Deborah, his owner, blames Annie. Deborah is out for revenge, blasting Annie on social media to make sure her cat-sitting days are over. It even seems that she’s the one leaving the nasty Yelp reviews for the Jumping Bean, so Annie’s on thin ice there, too.
Annie is immediately intrigued by Zoe due to her home’s opulence and her seemingly glamorous lifestyle. Most fascinating is the studio, with its closed doors and Zoe’s instruction to never, ever open them. But it’s when odd souvenirs pop up in the house–items that seem connected to active murder investigations–that Annie becomes obsessed. A huge fan of Cuppa Crime, a true crime podcast featuring the team Gary and Gail, she sees her investigation into Zoe’s truth as fodder for one of their episodes. Instead of her internal dialogue, or to supplement it, the reader has Gary-and-Gail banter. Will Annie emerge as a brilliant sleuth, or will she end up a murder victim of the clearly-up-to-no-good Zoe?
There are a lot of enticements in The Terrarium. We want to know what will happen with Annie’s feud with her former client. We want to know more about Charlotte, the Karen neighbor seems to pop up every time Annie reports for duty at Zoe’s. We want to know what befell Annie’s dear friend June, from college, as a suspicious or at least unfortunate end is alluded to. We want to know who Zoe really is and what she has going on behind the studio.
The Terrarium doesn’t fully deliver on its promises. Ultimately, these plot points are either not fully resolved, or they leave something to be desired. For example, Zoe doesn’t become an active character until near the end of the novel, with Annie observing the oddities of her mansion as an inactive participant. Charlotte does end up playing a role, but her motivation remains unclear. In mysteries such as this, reasons matter. Characters don’t just act for no reason.
But all is not lost. Remember, Annie is the star here–especially in her own head–and it’s Annie that makes The Terrarium worth the read. Annie is Helen Fielding’s Bridget Jones as an aimless, crime-obsessed, cat-loving sociopath, and it’s delightful how this persona is teased out until we fully understand her.
At first, Annie presents as the ultimate loafer, idly pocketing trinkets from clients who have entrusted her to cat-sit, snooping around, and riding her bicycle to perform her menial cat-and-coffee-related duties. But page by page, it becomes clear that Annie might not be as hapless or innocent as she seems, that maybe she has something more brewing behind the surface.
Readers may also appreciate the podcast format. Annie doesn’t have much of a social life, so Cuppa Crime’s hosts step in, both for companionship purposes and so Annie can feel important. She’s a hero in her own mind, as passive as she may be on the outside. And Gail and Gary are fun, with their back-and-forth banter.
All and all, with its twist and turns and oddball narrator, The Terrarium is a fun thriller, especially for folks who plan to read it with a cat on their lap. It’s different, Annie is fun, and no one can resist a thriller where it’s clear that a character will disobey instructions not to open a certain door.
*About the reviewer: Sarah Reida’s debut adult novel, Neighborhood Watch, received a Kirkus Star and was honored as an Amazon editorial pick as one of the Best Books of the Year So Far 2024. She is seeking representation for her sophomore novel, a small town mystery involving beer and murder. Join Sarah’s elite group of Instagram followers here.
