Plot summary

When Det. Lt. Stephenson investigates the murder of a doctor, who was found stabbed in his apartment, he learns that he had dinner with a woman named Teresa Collins the evening of his death. It looks like an open-and-shut case when several residents of the apartment building identify the woman. Then he discovers that she has a twin sister, Ruth, and neither will implicate the other as being the woman who was there. Dr. Scott Elliott, a psychologist who has made a study of identical twins, agrees to look into the case and concludes that one of them is insane. Complicating matters is the fact that he is falling in love with one of them.—garykmcd