A young police commissioner investigates the murder of a young woman, which occurred the previous night in a tram car. To solve the case, the commissioner is willing to do anything, even risk his girlfriend's life.

A patient at a psychiatric hospital appears to be the perpetrator of a murder. The police try to track him down, while a girl, trying to steal a doll, encounters a shady individual.

A woman claims to have witnessed a murder, but, having no evidence to provide, is not believed.