A decoding expert tangles with enemy spies.

A young girl is travelling to London to find work. Arriving at the station, she meets a man who has been stabbed by a member of a gang of crooks involved with greyhound racing. She becomes a suspect, but flees the scene in order to deliver a message to the dead man's brother. She is protected from the police by a night club entertainer, who she learns is the man she is seeking.