Two sailors get caught in a mountain of mix-ups when they meet their long-lost twins.

Oliver Hardy receives a letter from his mother that contains a photo of himself and his twin brother Bert, his friend, Stan Laurel, and Stan's twin brother Alf. The boys have not seen their twins in years, and Ollie's mother states that they went to sea and were hanged for mutiny. Ashamed to be related to such scoundrels, Stan and Ollie burn the photo and vow never to tell their wives, Daphne and Betty, about their brothers. That afternoon, however, the S.S. Periwinkle docks, and Alf and Bert prepare for shore leave. The ship's chief engineer, Finn, tricks them out of their money, and they are then summoned by the ship's captain, who tells them to get a package he is expecting and bring it to Denker's Beer Garden. The boys get the package and go to Denker's, where they meet two gold diggers, Lily and Alice, who set their sights on the pearl ring the boys are holding for the captain. The girls order expensive dinners for which Alf and Bert cannot pay. As security, Alf and Bert leave the captain's ring with the waiter, Joe Groagan, and rush to the boardinghouse where Finn is staying to retrieve their money. Finn refuses to give the money back and eventually tricks them again, leaving them trapped in the boardinghouse without any clothes. Meanwhile, Stan and Ollie go with their wives to Denker's to eat. Lily, Alice and Groagan, unaware that Stan and Ollie are not the men they met earlier, create all kinds of havoc for them. Finally, after paying Alf and Bert's bill, receiving the pearl ring in exchange for their cash and trying to placate their jealous wives, Stan and Ollie are done in by Finn, who mistakes them for Alf and Bert and their wives for Lily and Alice. After their wives storm out, Stan and Ollie join a congenial drunk and drown their sorrows. Back at the boardinghouse, Alf and Bert decide to find the captain and so, wrapped in quilts, they return to Denker's. Groagan and the bartender fight with them when they ask for the ring, and when the police take them away, they are mistaken for Stan and Ollie by Mrs. Addlequist, a friend of Daphne and Betty's. At the courtroom, other prisoners tell Alf and Bert that Daphne and Betty are social workers, while the wives plead with Judge Polk to release the boys. Alf and Bert are then united with "their" wives and they all go to a nightclub. Stan and Ollie are already there, and the chaos begins when Alice and Lily show up as well. The captain finds Stan and Ollie at the bar and asks them for his ring. Two gangsters overhear their conversation and see Ollie accidentally put the ring in Alf's pocket. The captain takes off in pursuit of Alf, and when Stan returns to Ollie, he and Ollie are kidnapped by the gangsters. Finn and some toughs join in the chase of Alf and Bert, and after demolishing the nightclub, they all go to the waterfront, where the gangsters have put Stan and Ollie's feet in cement. After accidentally knocking the gangsters into the water, the boys fall in themselves. Alf and Bert appear and, after returning the captain's ring, rescue their long-lost brothers. They realize that the day's mishaps are the result of mistaken identities, and all ends well until Bert and Ollie, complaining to one another about "those dumb Laurels," do not watch where they are going and fall off the pier.