Staying with a friend and her husband is sexier—and deadlier—than anyone could have imagined, in this "delightfully salacious" ( Shondaland ) domestic suspense novel from the New York Times bestselling author of the Reese's Book Club pick We Were Never Here .

"A fresh and sexy ride, perfect for reading poolside."— People (Best New Book)

"Sexy, atmospheric, deliciously creepy, and ingeniously plotted: the best kind of up-all-night page-turner."—Lucy Foley, #1 New York Times bestselling author of The Paris Apartment and The Guest List

Kelly's new life in Philadelphia has turned into a nightmare: She's friendless and jobless, and the lockdown has her trapped in a tiny apartment with the man she gave up everything for, who's just called off their wedding. The only bright spot is her newly rekindled friendship with her childhood friend Sabrina—now a glamorous bestselling author with a handsome, high-powered husband.

When Sabrina and Nathan offer Kelly an escape hatch, volunteering the spare room of their remote Virginia mansion, she jumps at the chance to run away from her old life. There, Kelly secretly finds herself falling for both her enchanting hosts—until one night, a wild and unexpected threesome leads the couple to open their marriage for her.

At first, Kelly loves being part of this risqué new world. But when she discovers that the last woman they invited into their marriage is missing, she starts to wonder if they could be dangerous . . . and if she might be next.

Packed with Andrea Bartz's signature tension, twists, and toxic relationships, The Spare Room marks an edgy, boundary-pushing new direction from the "master of the 'feminist thriller'" ( Los Angeles Times ).