Accused of murdering seven people, Ruth is locked away in a high-security asylum for a crime she swears she didn’t commit. No one believes her—her protests only mark her as insane. But Ruth isn’t alone in this nightmare. Her cell is next to Apex, a mysterious inmate whose voice travels through the walls, whispering in the dark. They’ve never seen each other or shared more than fragmented conversations, but their growing connection is the only thing keeping Ruth from unraveling completely. Then, one night, McRens—a sadistic guard—drags Ruth out for a brutal interrogation. When he returns her to her cell, he makes a fatal mistake—he locks her in Apex’s cell instead of her own. Ruth is trapped with a man she’s never seen face-to-face, but whose dangerous reputation is known throughout the asylum. Now, Ruth must confront the terrifying Is Apex her only chance for survival, or is he the final nail in her coffin?