A pair of sailors on leave try to help a movie extra become a singing star.

After eight months at sea, sailors Clarence Doolittle and Joseph Brady are granted a four-day shore leave in Hollywood, California. Joe, an incorrigible philanderer, plans to see one of his sweethearts while on leave, and later offers the shy and bookish Clarence advice on how to meet women. Clarence and Joe set out to find their shore leave romances but their plans are soon thwarted by a police sergeant, who demands that they help him with an unusual situation involving a young boy named Donald Martin. The police sergeant explains that Donald has run away from home to join the Navy and refuses to tell the police where he lives. Joe and Clarence easily win Donald's trust and agree to escort him home, where he lives with his widowed aunt, Susan Abbott. While Joe is eager to avoid any further involvement with the young boy, Clarence falls in love with Susan and promises to return the following day. When Joe and Clarence return to Susan's, they meet Bertram Kraler, a man Susan hopes will introduce her to the famous maestro José Iturbi. As Susan dresses for her date, Joe, convinced that Bertram is a new suitor who will only get in the way of Clarence's romantic pursuit of Susan, scares Bertram away by suggesting that Susan is a notorious Navy sweetheart. When Susan learns what Joe has done, she breaks down in tears and believes that her chances at breaking into show business are doomed. Joe tries to comfort Susan but only makes matters worse for himself when he tells her that Clarence and Iturbi are good friends and that he can arrange an audition for her. With her faith in Joe and Clarence restored, Susan takes them to a Mexican restaurant and sings a song for them. While Joe dances with Susan, Clarence meets a friendly waitress, whom he nicknames "Brooklyn," after their hometown. Realizing that he must honor Joe's promise to Susan for an audition with Iturbi, Clarence tries unsuccessfully to meet with Iturbi at the Metro-Goldwyn-Mayer studios. Meanwhile, Joe, who has become quite fond of Donald and Susan, tells Donald's classmates a story about his experience in a mythical kingdom populated by animals: In the kingdom, Joe discovers that the animals that live there are sad because their mouse king has prohibited them from singing. Determined to help the animals, Joe visits their unhappy king and shows him the beauty of song and dance. Joe's story concludes with the king repealing his edict and allowing the animals to sing. As a new romance develops between Clarence and Brooklyn, Joe falls in love with Susan. One day, Susan has a chance encounter with Iturbi and discovers that Joe and Clarence have been deceiving her and do not really know Iturbi. Feeling embarrassed and betrayed, Susan breaks down in tears. Iturbi, however, understands her situation and arranges a screen test for her. The test is a great success, and Iturbi soon presents Susan at one of his shows. Before returning to his ship, Joe makes amends with Susan, and Clarence and Brooklyn embrace.