Roman police detectives interrogate a series of potential perpetrators in their struggle to determine whom to arrest for the brutal murder of a beautiful prostitute whose body is discovered in a park on the day of a torrential rainstorm. One by one, the prime suspects -- girl-crazy teenager Nino, pickpocket Canticchia, a soldier on leave, a tourist and a pimp -- recount the events of the day to the police, each insisting he is innocent.
