After a good-natured Irish cop is framed for a diamond robbery and murder and presumed dead in a train wreck, he gets plastic surgery and returns to expose the real killers.

A veteran, Joe Hilton, returns from the war to find that his brother Jeffrey Hilton, a gangster, has been killed. His quest for revenge leads him to take over his brother's illegal operations but his sweetheart, Lynn Turner, persuades him to change his ways and return to the straight and narrow.

Wharf-master Buck Elliot is the leader of a band of murderous crooks. The gang shoots down a policeman in a wharf side scuffle, and Detective Donovan swears revenge on the murderer.

Beau Nash is a "gentleman crook" who headquarters his gang of jewel thieves in a run-down boardinghouse. When one of his gang, Mike, gets arrested, his sister Claire--aka "Lady Byron"--swears to get revenge. The gang frames Donald, the best friend of the detective who arrested Mike, for a jewelry store robbery. The detective gives Donald--and his new love, Claire--a short time to find the thieves and clear his name before he takes him in.