On the day of his wedding to Terry, band leader Kay Kyser receives a telegram notifying him that he has been drafted and ordering him to report to camp that afternoon. As a result, Kay is forced to leave his bride immediately after the ceremony. At camp, the army brass discovers that they have inducted the wrong Kyser and after discharging Kay, ask him to join a government espionage unit investigating saboteurs operating from the Orchid Room, the ballroom in which Kay's band performs. Kay is ordered to tell no one of his assignment, and returns to civilian life, disgraced by being publicly discharged for flat feet. Kay is about to spend his first night alone with Terry when an agent phones and directs him to a waterfront dive where he is to meet his contact, Connie. At the docks, as Connie and Kay venture out into the foggy night, they witness the murder of one of their associates. In his zeal to escape, Kay rams a police car and spends the night in jail. Hoping to avoid Terry's wrath, he returns home the next morning, carried in on a stretcher, and claims that he was hit by a truck. Terry believes Kay's story until she reads the morning headlines about his arrest with a mysterious woman and stomps out of the apartment. Soon after, Kay's arranger is killed by Harry Robinson, a spy working undercover as the manager of the Orchid Room. Robinson substitues another spy as Kay's new arranger, and when Major Allen, a member of U. S. Army Intelligence, analyzes the musical score, he realizes that the notes form a coded message to be braodcast over the airwaves. Kay returns to his apartment to find Terry waiting for him, and the newlyweds are about to kiss and make up when Connie calls with instructions to meet her in ten minutes. To produce an alibi for his abrupt departure, Kay throws a flower pot at a police officer walking his beat, and when the officer comes to arrest him, Kay handcuffs him to the railing in the elevator. Kay's ruse fails, however, when Terry sees Kay and Connie climb into a cab together, and she files for an annulment. To lend credibility to Kay's disillusionment with his country, Connie instructs him to make unpatriotic remarks at a rally in the park. His remarks spark a fight with two marines, and when Robinson learns that Kay has been arrested for creating a disturbance, he takes the bait and informs the band leader that he plans to visit the Kysers that night at their apartment. Major Allen dispatches Connie to pose as Kay's wife, and when Terry returns to the apartment, Connie locks her in the closet. Soon after, Robinson and the others arrive and announce that they are taking Kay to headquarters to meet the chief. Connie assures Kay that she will trail them and send Major Allen and his men to his rescue. Immediately after Kay leaves, however, Terry struggles free and locks Connie in the closet. Meanwhile, Robinson has sensed that something is amiss, and when they reach the boarded-up theater that serves as headquarters, he accuses Kay of working for Army Intelligence. Kay is calmly awaiting Connie's reinforcements when Terry bursts in and accuses Kay of deceiving her. Dismissing Robinson's threats as another ruse, Terry slugs Kay. When the spies leave the room, Kay and Terry escape through a secret panel, but Terry still refuses to believe that they are being held captive by a gang of spies and informs Kay that she locked Connie in the closet. The spies capture Terry as she runs across the stage, but when one of the gang swings an ax at Kay, he misses and cuts the ropes to the curtains instead, sending them crashing down on the spies. After Kay subdues the saboteurs by smacking them on the heads with a mallet and nailing the curtain to the floor, he is hailed as a hero. As he and Terry return triumphantly to the Orchid Room, he encounters the officer he handcuffed in the elevator and is arrested. Determined not to spend another night without her husband, Terry cracks a flower pot over the officer's head, and the newlyweds spend their first night together in adjoining cells.