As the luxury liner the S. S. Transatlantic is about to set sail, lens grinder Rudolph Kramer, a passenger aboard the ship, tells his daughter Judy how pleased he is to be able to take her on a trip for which he has been saving for all his life. Also traveling on the Transatlantic is the suave Monty Greer, a "baggage smasher" who specializes in absconding with bags belonging to wealthy passengers. Monty's rival, crime leader Handsome, is also on board, as are banker Henry Graham and his wife Kay, his intended victims. The Grahams soon become embroiled in a quarrel when Kay accuses Henry of keeping the young Sigrid Carlene as his mistress. Later, when Monty enters Henry's cabin on the pretext of searching for his misplaced bags, he is discovered by Henry. Monty apologizes for the intrusion and then scouts Kay's room next door. Soon after meeting Judy, Monty and she become fast friends, and Judy tells him that all of her father's assets lie in the Graham Investment Corporation of New York. Once at sea, the Transatlantic receives a wired message that the Graham Investment Corp. has failed for the lack of twenty million dollars. Though Henry is saved from the bankruptcy because he is carrying personal securities, Rudolph is financially ruined by the failure. Rudolph becomes despondent, and when he pleads with Henry for financial help, Henry coldly refuses and has him removed from his room. While Handsome prepares to make his move on Henry's securities, Judy tells Monty that she is concerned about the threats her father has made against Henry. Shorty thereafter, Monty hears a shot ring out in Henry's room. Upon entering the room, Monty sees Rudolph holding a gun. To protect Rudolph, Monty orders him and Judy out of the room and then wipes Rudolph's fingerprints from the gun. During a shipboard investigation into the murder, the robbery plot is discovered and Rudolph and Monty are confined to the brig by the captain. There, Rudolph confesses his intention to shoot Henry, but insists that the shot that killed Henry came from another gun. Convinced that Handsome fired the gun, Monty goes after him, and the two face off in a boiler room shootout. After Handsome is shot, he confesses to shooting Henry and robbing his cabin. All ends happily when Kay agrees to give the Kramers financial assistance and Monty kisses Judy.