It’s been a shattering year for seventeen-year-old Zoe, who’s still reeling from her father’s shockingly sudden death in a caving accident and her neighbors’ mysterious disappearance from their own home. Then on a terrifying sub-zero, blizzardy night in Montana, she and her brother are brutally attacked in a cabin in the woods–only to be rescued by a mysterious bounty hunter they call X.

X is no ordinary bounty hunter. He is from a hell called the Lowlands, sent to claim the soul of Zoe’s evil attacker and others like him. Forbidden to reveal himself to anyone other than his victims, X casts aside the Lowlands’ rules for Zoe. As X and Zoe learn more about their different worlds, they begin to question the past, their fate, and their future. But escaping the Lowlands and the ties that bind X might mean the ultimate sacrifice for both of them.