Ten years ago, fifteen-year-old Scarlett Crosby was held captive in a terrifying ordeal with a girl named Della. Scarlett escaped, their predator was killed, and Della simply vanished. Detective Kevin Dawson always wondered if Della even existed.

A decade later, Scarlett is a successful artist. As hard as she tries to move on, the mysterious Della remains her inescapable obsession. Then a girl's body is discovered—a link to Scarlett's horrific past—and all her old traumas resurface. So does Della. Scarlett has seen her hiding in plain sight. The girl who knows Scarlett's secrets, who understands the desperate compromises Scarlett made to endure hell, and who, like Scarlett, embraced the darkness to survive.

As a suspicious Detective Dawson once again comes calling, and obsessions turn deadly, Scarlett fears there isn't a living soul she can trust. As for Della, who's watching from afar, what could she possibly want from Scarlett now? And what new nightmare lies ahead?