In 1940, the testimony of Chief Petty Officer Mike Mallory (Pat O'Brien) at a United States Navy board of inquiry regarding a fatal gun turret accident helps end the career of Lieutenant Tom Sands (George Murphy). The situation is complicated by the fact that Sands and Mallory's sister Myra (Jane Wyatt) are in love. Afterward, Sands resigns his commission and breaks up with Myra, telling her there is no future for them.
In this voice over (Ronald Reagan) reenactment documentary, we follow the events of Captain Hewitt T. Wheless career as an bomber pilot for the US Army Air Corps during World War II. The story ranges from when Wheless joined in 1938 just before the war, through theoretical and practical training and education at Randolph and March Fields. He piloted a bombing mission in the Philippines early in the war, which resulted in his bomber plane being severely damaged after being attacked by a total of eighteen Japanese fighter planes in the air. A recording of a speech made by President Roosevelt, praising the pilot's extraordinary service, is highlighted. Captain Wheless at the end of the film gives a speech at the Boeing factory in Seattle, complimenting the workers.
During World War II, well-connected, Harvard-educated Lieutenant Gregg Masterman (Robert Taylor) enjoys his cushy posting as junior aide to Rear Admiral Stephen "Old Ironpants" Thomas (Charles Laughton), playing tennis and arranging social events. During a chance encounter, he gives bad advice to up-from-the-ranks Lieutenant Commander Martin J. Roberts (Brian Donlevy) out of spite. As a result, Thomas gives Roberts command of an obsolete, World War I-vintage destroyer, the Warren. To his dismay however, Masterman finds himself assigned by Thomas as Roberts' new executive officer. When Masterman learns that Henry Johnson (Walter Brennan), the ship's civilian caretaker, was a member of the Warren's original crew, he helps him reenlist and serve aboard his beloved ship.
The film's opening credits state that the screenplay was written by W.R. Burnett and Frank Butler "From the Records of The United States Marine Corps", and includes many Marine Corps and military advisers. It also states that "In this picture, the action at Wake Island has been recorded as accurately as possible. However, the names of the characters are fictional and any similarity to the personal characteristics of the officers and men of the detachment is not intended." This is likely because the actual events were unfolding during the production of the film, and names were being protected.
Slicker Smith and Herbie Brown (Abbott and Costello) are sidewalk peddlers who hawk neckties out of a suitcase. They are chased by a cop and duck into a movie theater, not realizing that it is now being used as an Army Recruitment Center. Believing that they are signing up for theater prizes, they end up enlisting instead.
Popular crooner Russ Raymond (Dick Powell) abandons his career at its peak and joins the Navy using his real name, Tommy Halstead. However, Dorothy Roberts (Claire Dodd), a reporter, discovers his identity and follows him in the hopes of photographing him and revealing his identity to the world.
After an air raid exercise in Los Angeles involving 18 Boeing B-17 Flying Fortress bombers, one of them goes down in the desert on its way back to base. Mysteriously, the dead body of a woman is found in the wreck. The pilot, Jefferson Young III (Ray Milland), is accused of having an unauthorized passenger on board and charged accordingly for disobeying orders. Before the court martial decides on a ruling, they review Jeff's military background and history.
Hotshot Ensign Alan Drake (Robert Taylor), fresh from the flying academy at Pensacola, Florida, wants to be accepted by the pilots of an elite service corps, nicknamed the "Hellcats", to which he has been posted. He gets off to a bad start, being forced to ditch his aircraft in heavy fog and mistaking Squadron Commander Billy Gary's (Walter Pidgeon) wife Lorna (Ruth Hussey) as a possible date. She is attracted to the young man, which leads to friction in her relationship with her husband.
After each is accepted for admission to Navy, three midshipmen, Dick Gates, Roger Ash and "Truck" Cross, become roommates. Dick is the scion of a wealthy family, Roger a former star football player for another university, and Truck a sailor appointed from the fleet. With a common love of football, all three go out for the plebe squad. Dick is tricked into committing a rules violation by a disreputable upperclassman with a penchant for hazing and is severely paddled. Even though hazing is forbidden by regulations, Roger decides to get even on his own terms. Despite his egotism, his classmates as well as the upperclassmen respect him when he challenges the abuser to a boxing match and wins it.
Seaman "Bake" Baker (Fred Astaire) and Sherry (Ginger Rogers) are former dance partners, now separated, with Baker in the Navy and Sherry working as a dance hostess in a San Francisco ballroom, Paradise.
Riveter "Chesty" O'Conner (James Cagney) and his best friend, "Droopy" (Frank McHugh), join the US Navy to annoy O'Connor's nemesis, Chief Petty Officer "Biff" Martin (Pat O'Brien). O'Conner gets himself court-martialled for being AWOL while visiting Martin's sister Dorothy (Gloria Stuart). Disgruntled at his treatment, O'Connor angrily derides the Navy and finds himself ostracized by his fellow sailors.