If you’ve ever roadtripped between Leavenworth and Spokane and gotten lost south of Coulee City, you may have found yourself gazing on the foamy shores of Soap Lake, known as “Washington’s Health Resort” for its healing, nutrient-rich mud and alkaline waters.

Author Matthew Sullivan’s second novel, “Midnight in Soap Lake,” imagines a remote, slightly sinister rural community, where generations of children have been raised to fear TreeTop, a menacing figure in a hazmat suit who terrorizes the local orchards, feeds on barn kittens and may be responsible for more than one mysterious death. Sullivan delivers a satisfying thriller that is loaded with flawed characters, complex motivations and a plot twist or two to keep the pages turning.  

Per the book description, “Midnight in Soap Lake” depicts a town “a town to rival Twin Peaks and Stephen King’s Castle Rock.” (Photo courtesy of Matthew Sullivan)

When newlywed Abigail’s husband Eli convinces her to move to Soap Lake so he can do research on the lake’s extremophiles — microorganisms that live deep below the surface where nothing else can — she gets excited to see The World’s Largest Lava Lamp but discovers only its base; the lamp itself allegedly held up in the review process. 

Then Eli jets off to Poland to study with a prestigious limnologist for six months, leaving Abigail to her own devices. Her only social interactions are limited to the newspaper delivery person, the pizza guy and the gas station attendant, so Abigail spends hours walking miles alone along irrigation canals through the surrounding orchards. 

One day, instead of the usual coyotes or quail, she encounters a young boy in yellow pajamas. He runs straight for her and wraps his arms around her legs. He’s covered in crusty blood. He brings her back to an abandoned car where there’s a woman behind the wheel, a large screwdriver embedded in her chest. The boy’s mom: dead. Suddenly, Abigail has a purpose. 

Matthew Sullivan’s debut novel, “Midnight at the Bright Ideas Bookstore,” was an IndieNext pick and a Barnes & Noble Discover Pick. (Photo courtesy of Heather Young)

Abigail befriends her neighbor, Sophia, a former junkie turned library clerk, and Officer Krunk, a hunky local cop, who fills her in on the local lore about the boy’s mom, Esme. Esme’s high school boyfriend was murdered by Silas, the neanderthal son of Pastor Kurt. As she digs further into Esme’s past, Abigail keeps brushing into evidence that TreeTop is afoot — and that somehow, jars of lake water are at the heart of the disturbance plaguing the town. 

“Midnight in Soap Lake” has it all — ripping dialogue, conspiracy theories, relatable and well-drawn characters, and suspense. Despite the subject matter (lava lamps, meromictic lake water with unknown and possibly superpowered organisms), colorful cast and abundant humor, Matthew Sullivan reins things in and delivers a straight-up thriller that’s not over-the-top or farcical. 

He introduces us to a part of Washington that’s lesser-known and intriguing — and could be worth a visit, if you can handle the stench of rotten eggs and the specter of TreeTop lurking amongst the fruit trees. 

This mystery is available at your local library in various formats: book, eBook and eAudiobook. Visit wcls.org to place a hold.

Christine Perkins is executive director of the Whatcom County Library System, wcls.org.