Underworld king Lee Lother has been killed aboard a ocean liner, several people could have been the murderer. There is his mistress Anya Roysen, a married woman, who was jealous of his flirtations with his old moll, night club singer Sally Marsh, who had agreed for one last night with Lother, to get her younger brother Ned out of the Lother's clutches because he has faked Lother's name on a check to pay his gambling debts. Then there is Sally's new flame Jimmy Brett, a con man and gentlemen thief, who has out-tricked Lother in a fixed poker game, and is, together with shorty, after the ladies jewels. Inspector McKinney suspects Joe Saunders, a recently released convict, who was arrested due to some tips by Lother, but Ned and Sally insist that they committed the crime alone.