In London, young Geoffrey Braemer works with thieves Doris Clandon and Jim Hampstead by posing as a spoiled rich boy, then swindling jewelry stores out of expensive merchandise. Although Doris and Jim manage to evade arrest, Geoffrey is caught during one of the robberies and is sent to Dr. Barnardo's home for orphaned boys. Geoff scoffs at the discipline of the school, which is a mariner's academy, even though the other boys are happy there. He constantly fails at his attempts to become "sea-worthy" and frequently is at odds with his peers. One day, Mrs. Briggs, the kindly wife of the school's headmaster, Captain Briggs, invites Geoff to take "liberty" at a party in their home. During the party, Geoff tells Albert Baker, a younger boy who has befriended him, that he is planning to run away. After he leaves, Albert asks Terry O'Mulvaney, one of the school's leaders, to find Geoff so he won't be sent to reform school. Terry reluctantly goes after Geoff and makes him come back, but only after hitting him first. As the boys re-enter their dormitory, Terry is seen, but he refuses to inform on Geoff and so is told that he will not be allowed to go on a student cruise on the Queen Mary . Geoff is then "sent to Coventry" by the other students, who refuse to speak to him. Some time later, when patron John Cartwright offers a trophy for the winner of the annual lifeboat race, instructor "Crusty" Jelks, who has become fond of Geoff, makes him his coxswain. After they win the trophy, Geoff feels remorse over having let Terry be punished for his offense and secretly tells Captain Briggs the truth. Geoff is just beginning to grow attached to the home, when Jim and Doris, pretending to be neighbors, offer to give a party for the boys and secretly try to convince Geoff to come back with them. Geoff refuses, and says that he wants to stay and sail on the Queen Mary , but as he leaves, they put some stolen jewels in his pocket. Mrs. Briggs later finds the jewels and asks Geoff about them, but he refuses to talk. Eventually he does confess everything, however, and the boys help him to apprehend Doris and Jim. Finally, Geoff knows that he really has found a home and looks forward to the cruise on the Queen Mary with Terry and Albert.