As a massage instructor, Kathy Barrister has devoted her life to promoting peace and inner strength. Then Erin, Kathy's protégé, is brutally murdered by a serial killer stalking online prostitutes who use massage therapy as a legal pretense. Kathy's investigation plunges her into a world of dark corners and self-recrimination when she discovers the truth about Erin's secret life. As the murders continue, Kathy realizes the killer must be close to her—maybe even one of her current students. Stopping him becomes Kathy's obsession, even if it means making herself his next target.