When a retired gangster is murdered offshore of a popular seaside recreation area, the police department and the beach patrol join forces to bring the man's killer to justice. Their only lead is the dead man's girlfriend, a singer in a third-rate night club, but the woman was on stage when her meal ticket was shot. Using data produced by the beach patrol, the police learn where the man was killed and are surprised when the man's girlfriend is discovered scuba diving in the vicinity the day after the crime was committed.
