Arrogant Chris Winters is ordered by his father, Capt. Christopher Winters, to join the Marines after he is expelled from Culver Military Academy for misbehavior. Disregarding his father's plans for his future, Chris intends to take a cushy desk job provided by the influential father of his girl friend, Helene Hunt, after he finishes basic training. Capt. Winters has written to his old friend, Sgt. Dixie Smith, asking him to toughen up Chris, and Dixie, who will be Chris's drill sergeant, takes an immediate dislike to the sarcastic recruit. The night Chris arrives at the Marine Base in San Diego, he meets Mary Carter. Chris, unaware that Mary is a Navy nurse, is impressed by her beauty and spirit and tries, half-successfully, to romance her. Mary is frightened by her attraction to Chris, however, and cuts short their evening. The next day, Chris begins training, along with fellow recruits Johnny Dent, Okay Jones, Mouthy and Butch. Chris easily masters the tasks assigned by Dixie, then helps the earnest but clumsy Johnny. Chris attempts to pursue a relationship with Mary, but she reveals that, as a nurse, she holds rank equivalent to a lieutenant and cannot fraternize with enlisted men. Mary is troubled by Chris's lack of devotion to the military, but is still jealous when Helene appears on the base one day and gets Chris to take her out. Later that evening, when Chris returns, he assures Mary that he cares only for her, and that if he takes the office job in Washington, they can conduct their romance openly. Mary turns Chris down, and soon after, Chris has more problems when he starts a fight with Dixie, whom he accuses of bullying Johnny. Chris and Dixie are arrested for the fistfight, and despite the damage it causes his career, Dixie states that he started the fight so that Chris will not get into trouble. Chris's barracks mates, angry that he caused Dixie's demotion, snub him, and Chris decides to leave with Helene. Before they can leave the camp, however, emergency maneuvers are called and Chris goes with the others to practice night maritime shelling. As Dixie leads the men in cleaning up the floating targets, he is knocked unconscious, and no one notices his disappearance until they return to the main ship. Despite the shelling, Chris finds Dixie and rescues him just before the target he is on is destroyed. Once Dixie recovers, Chris reveals that he risked his life only to erase the debt he owed Dixie for lying about the fight, and that he still intends to leave. Chris then asks Mary to accompany him, but she again replies that she belongs in the service. Chris departs with Helene, but while in the taxi, they hear a radio report about Pearl Harbor. Helene declares that the report is a fabrication concocted by Orson Welles, but when Chris sees Dixie leading his regiment through the crowd, he realizes that he truly is a Marine and must join the fight. Chris dons his uniform as he marches with the men, who are glad to see his change of heart. As they board the ship bound for overseas duty, Chris notices that Mary is already aboard, then waves goodbye to his father.