Vito is a former French secret service agent gone bad whose specialty is recruiting nice young couples and turning them into heartless killers. In Rome, a sultry young woman, Carla, has disquised herself in a blonde wig and black miniskirt in order to kill four people in the middle of the city with the help of her husband. However, a shy engineer, Dario, lives next door to the couple and decides to videotape their crimes. His wife, Luciana, later decides to help him entrap this killer couple.