A backpacking trip has deadly consequences in this "eerie psychological thriller . . . with alluring locales, Hitchcockian tension, and possibly the best pair of female leads since Thelma and Louise" (BookPage), from the bestselling author of The Lost Night and The Herd.

"Bartz takes the idea of a 'frenemy' to new heights. . . . [An] expert vivisection of female modes of communication and competition."-Los Angeles Times (Best Books for Summer Beach Reading)
A Marie Claire Book Club Pick • Named One of the Most Anticipated Books of the Year by Oprah Daily, BuzzFeed, Reader's Digest, Men's Journal, and CrimeReads

Emily is having the time of her life-she's in the mountains of Chile with her best friend, Kristen, on their annual reunion trip, and the women are feeling closer than ever. But on the...