A teenage girl sneaks out of her father's house for an assignation with an older man. While the couple are making out, an armed robber sneaks up beside their car and kills the young man when he refuses to give the crook his wallet. Fearing her father will punish her for seeing the young man over his objections, the teenager refuses to assist the Harbor Command with their investigation. Listening to the police radio band, the crooks learn the girl's identity and determine to eliminate the witness before she changes her mind.
