To infiltrate a gang of jewel robbers, Baretta seeks the help of a former expert safecracker he once sent to prison.

When a dying hoodlum entrusts his girlfriend with a detailed record of all his underworld activities, she is sought by both the police and his former cronies seeking to protect themselves.

Even though he has no evidence, Baretta suspects a man named Mazurski of killing a petty criminal. His hunch is based on the man's wife Doris being injured during a burglary committed by the now dead man.