Inspector Jessica Shepard is under pressure to prove herself after being promoted and reassigned to the homicide division. What better way to do it than by solving San Francisco's newest murder? However, as Shepard and her partner, Mike Delmarco, quickly discover, the victim and Shepard had a romantic relationship. As more of Shepard's ex-lovers are discovered dead, her mind becomes increasingly unstable, and she begins to suspect that she may be the very criminal she is pursuing.