Lee Lother, an underworld king, is murdered on an ocean liner, and several individuals are suspected of being the culprit. Anya Roysen, Lother's mistress, is jealous of his relationship with Sally Marsh, a nightclub singer. Sally, in turn, agreed to spend one last night with Lother to free her younger brother from his grasp. Meanwhile, Jimmy Brett, a con man and thief, and Shorty plot to steal the ladies' jewels. Inspector McKinney suspects Joe Saunders, a recently released convict, who Lother had previously reported. However, Ned and Sally insist that they acted alone in the murder.