Haunted by failure, former FBI profiler Caroline Bennett is drawn back into the world she fled when a disturbed artist takes a girl hostage. After brilliantly rescuing the victim, she realizes the true killer is still at large—a phantom mastermind known as "The Controller," who turns psychologically vulnerable people into his pawns. As Caroline hunts a killer who never leaves a trace, she is pulled into a deadly cat-and-mouse game where the mastermind is always one step ahead, and the danger is closer to her own family than she could ever imagine.