After he is drafted, Dorian "Dodo" Doubleday, an information clerk in a railroad station, puts his photographic memory to use by memorizing entire manuals on Army procedure. Unfortunately, when he reports for basic training at Camp Carver, Dodo's encyclopedic knowledge of military protocol makes him unpopular with his fellow recruits and gets him off to a bad start with his drill instructor, the tough-as-leather Sergeant Ames. The officers are impressed, however, and Dodo is immediately made a sergeant and put in charge of the notoriously undisciplined Company F. When the soldiers mock Dodo's orders by reporting for training wearing nothing but overcoats, Ames, gleefully anticipating Dodo's downfall, hastens to tell Major Greer. Dodo improvises a story about experimenting with minimal equipment in case of a surprise attack, adding that his men are a hardy breed from the Kentucky hills and can march better without shoes. Greer has the barefoot soldiers march in formation all day, and at a dance that evening, the young women flock admiringly around Dodo. The next day, Ames sees Dodo's men carrying out sentry duty on bicycles, in taxis and on a mule. After the mule disrupts the marching band, Captain Rossmead angrily sentences the men to the guard house, but Dodo takes the blame, and, to Ames's dismay, Rossmead dismisses the matter. Dodo's gesture earns him the men's respect and loyalty, and they swear to stand behind him and become good soldiers. Determined to see Dodo put in his place, Ames urges Rossmead to assign Dodo to serve as orderly to the new post commander, Colonel "Spitfire" Barkley. In Barkley's quarters, Dodo finds the eccentric colonel, who is intimidated by microphones, nervously practicing for an upcoming radio address to the troops. While Barkley is in the shower, Dodo accidentally spills powder on the colonel's jacket and hat, and as he is brushing them off, he cannot resist trying them on. Just then, Dodo's girl friend Jeanne, who has joined the Buddies Entertainment League to be near him, comes along and sees him in the colonel's uniform. Jeanne assumes that he has been promoted to colonel, and Dodo cannot bring himself to correct her, even when an escort arrives to take the "colonel" to the radio station for his speech. Standing before the microphone, Dodo gradually warms to his subject, the importance of military service, and the speech, which is broadcast throughout Camp Carver, is a huge success. Ames and Rossmead bring Dodo back to Barkley's quarters, and as Dodo is guiltily removing the uniform, congratulatory calls begin coming in from Washington. Barkley is pleased and asks Dodo to write down the speech for him, and Ames becomes the colonel's new orderly.