After the famous Navy destroyer the S. S. John Paul Jones is sunk in the South Pacific during World War II, the Navy commissions a new destroyer to carry on her name and tradition. Steve "Boley" Boleslavski and Kansas Jackson, veterans of the World War I escapades of the Jones , proudly help build the new vessel. At her christening, Boley meets his old shipmate Clark, the commander of the new Jones . Their reunion gives Boley the idea of re-enlisting to serve on the Jones , but headquarters denies his request and assigns him to train recruits in San Diego instead. At the Naval base there, Boley is reunited with Kansas Jackson, one of his recruits. When his trainees are assigned to the Jones , Boley asks Clark to appoint him chief bosun's mate of the ship. Although Clark has already assigned Mickey Donohue to the position, he agrees to request Boley as his mate. Boley's appointment transforms him into a martinet, and he soon earns the animosity of the entire crew including Donohue, who has been re-assigned as gunner's mate. To insure cooperation between the two men, Clark arranges for Boley's daughter Mary to meet and woo Donohue. The ship's shakedown cruise results in disaster, and the malfunctioning equipment on board serves to inflame the already testy relations between Boley and his men, resulting in Boley's demotion. After Donahue is appointed the new mate, he agrees to allow Boley to remain onboard for Mary's sake. When a fire erupts in the engine room during the ship's speed trial, Boley risks his life to save the trapped crew members. Once the ship docks, Boley is ordered to remain onshore because of injuries he sustained in the fire. The ship is then assigned to carry mail because of her failure during sea trials, and the crew thinks that the vessel is jinxed and many apply for transfers. Meanwhile, Donohue proposes to Mary, and they secretly elope to avoid telling Boley of their marriage. When Boley returns to the ship and finds the crew packing, he rallies their spirits by recounting the heroics of Admiral John Paul Jones and the "tub" that he commanded. The men decide to remain onboard, and the ship sets sail for Dutch Harbor in the Northern Pacific. When Japanese bombers begin attacking American ships, the Jones is ordered into battle. Just as Washington rescinds the ship's permission to join the battle, she is attacked by Japanese planes. Although her hull is punctured by bombs, her artillery guns down all the enemy aircraft. Stalked by an enemy submarine, the Jones begins to sink and her engine fires are extinguished by the onrushing water. When the order comes to abandon ship, Boley begs for a few men to repair the rupture. Boley and his crew toil throughout the night, and with only thirty minutes remaining before daybreak, the repairs are completed and the ship's engines are fired. When the Japanese submarine surfaces to torpedo the Jones , the ship releases her depth charges. As the crew in their lifeboats cheer, the Jones then rams and sinks the enemy submarine. Both the Jones and Boley are redeemed by their act of heroism, and their victory is heralded throughout the country. Content with his success, Boley decides to leave the ship when it docks and is awarded the crew's admiration and the Jones commission pendant. When he steps onto the pier, he is greeted by Mary, who introduces him to her new husband, Donohue.
