Just out of jail and vowing to go straight, former jewel thief Boston Blackie, undertakes the reformation of a pretty blonde who has stolen a necklace from a cabaret dancer. He learns that the jewel belongs to the mother of the blonde girl, and the blonde's philandering father gave it as a gift to the cabaret girl. Now, Blackie must find a way to return the necklace to the owner's safe without arousing the suspicions of the girl's family.