A convicted female blackmailer is found murdered in her flat and suspicion falls on three men, all of whom the police believe may have had reason to wish her dead

A jeweller is killed in a gang robbery leaving the daughter as the only witness. When the police can't build a case against him she decides to go undercover to infiltrate the home of the killer's brother. Slowly she is drawn into the world of the rival gangs.

Despite seemingly having everything (a husband, children, a house), Jean is unsatisfied.