The four Marx brothers stow away on an ocean liner and fraternize with racketeers in this punny comedy written by S. J. Perelman and Will B. Johnstone.
Groucho, Chico, Harpo, and Zeppo have spent two days living in four barrels, Chico saying he would send for his grandfather's beard by "hairmail." When a search discovers them, they run away, set up as an orchestra, and then hide in various ways. Groucho complains to the captain that no one sneaked into his stateroom. He says he is a stockholder, explaining that the "stockholder of yesterday is the stowaway of today," a reminder of the recent stock-market crash. He and Chico lock the captain in a closet and eat his dinner. Harpo hides in a Punch and Judy puppet show and entertains the children as the authorities try to capture him. Groucho is trying to make time with Briggs' wife Lucille by hanging out in her closet. The racketeer Briggs gives Groucho and Zeppo pistols to protect him.
Harpo and Chico observe a chess game and then take it over. They scare Briggs away and show the other racketeer Helton how tough they are by having Harpo slug Chico. Helton then gives them pistols to protect him. When Groucho sees Mr. and Mrs. Briggs quarreling, he gives them his pistol. Zeppo tells Mary Helton that he'll never leave her; but just then someone comes looking for him, and he runs off. They need passports to get off the boat, and Zeppo has stolen the passport of Maurice Chevalier. They each sing as though they are he, except that Harpo uses a phonograph; but they are each sent back. After a man faints and Groucho passes himself off as a doctor, they escape the ship on the stretcher.
Always ready to save money, Groucho gives the taxi driver a dollar and says keep the change. The driver replies, "I said a dollar ten." Groucho snatches the dollar back and quips, "Then I'll keep the change." At Helton's high society party Chico plays the piano and Harpo the harp. Zeppo's sweetheart Mary Helton is kidnapped and taken to a barn. The four Marx brothers manage to rescue her as Zeppo wins a fist fight announced as a sporting event by Groucho; finally Zeppo gets Mary.
This zany story is filled with wit and charm by the immensely talented brothers, who use their wits to survive on nothing among the rich. The absurdity of wealthy people on a luxury cruise during the depression and a racketeer throwing a high society party are the background for their antics that seem to make fools of just about everyone.