After witnessing a hold-up In which a bogus police car is used, Roy Evans refuses police protection and sets out to hire a gunman to protect his young daughter and himself. Nick is assigned to the job and works his way into Evans's confidence.

Diamond-cutter Ernie Kovacs is shot when three thieves steal a priceless uncut diamond from his office. At the hospital. Kovacs remains silent when the police question him. Undercover man Nick is put on the case