Sex Killings or Serial Killer? In Act of Evil, police detective Teri Harmon investigates the sadistic murders of three women. Teri and her partner, detective Garcia, better known as Chuey, are aided by Dr. Shelby Martin, psychiatrist and widower. Teri feels an increasingly strong sexual attraction to Shelby, but he is captivated by Marian Barlow, the most influential woman in the county. Shelby's affinity for Marian is mutual, and their affair is torrid and on the kinky side. As chairperson of the Women's Defense League, Barlow pressures Teri and the police to find the man responsible for the killings before more women fall victim to the sadistic killer. The case leads Teri from the stifling San Joaquin Valley to cool but unconventional San Francisco and its lesbian world and back again—with a surprising but enlightening side trip to Texas. In the suspenseful denouement, Teri discovers she must rescue Shelby before he becomes the victim of the killer and his own folly.