In 1941, bugler Private Robert E. Lee Prewitt transfers to G Company on the island of Oahu. Captain Holmes has heard he is a talented middleweight boxer and wants him to join his regimental boxing team. Prewitt refuses, having stopped fighting after blinding his sparring partner. Holmes is adamant, but so is Prewitt. Holmes makes life as miserable as possible for Prewitt, hoping he will give in and orders First Sergeant Milton Warden to prepare court martial papers after Sergeant Galovitch insults Prewitt to goad him, then gives an unreasonable order which Prewitt refuses to obey. Warden, however, suggests that he try to get Prewitt to change his mind by doubling up on company punishment. The other non-commissioned officers assist in the conspiracy. Prewitt is supported only by his friend, Private Maggio.
Warden begins an affair with Holmes' neglected wife Karen. As their relationship develops, Warden asks Karen about her affairs to test her sincerity. She says that has been unfaithful to her husband for most of their marriage having had to undergo hysterectomy as a result of being infected with an STD by her husband after he had visited a prostitute. Prewitt and Maggio spend their liberty at the New Congress Club, where Prewitt falls for one of the whores, Lorene, who is saving all she earns in pursuit of a respectable life back on the mainland.
Maggio and Staff Sergeant Judson nearly come to blows at the club. Judson warns Maggio that sooner or later he will end up in the stockade, where he is the Sergeant of the Guard. Karen tells Warden that if he became an officer, she could divorce Holmes and marry him. Warden reluctantly agrees to consider it. Warden starts to fall in love with Lorene. Both men, broke, try and make some extra cash by flirting with men at a local gay club, where they spot Bloom, another member of the company. The military police arrest Maggio, and he is sentenced to six months in the stockade, where he is beaten to death. Their friendship is mocked by Judson. Prewitt tracks Judson down and kills him with the same switchblade Judson pulled on Maggio earlier, but sustains a serious stomach wound and goes into hiding at Lorene's house.
The Japanese attack Pearl Harbour. Prewitt attempts to rejoin his company under cover of darkness but is shot dead by a patrol. Warden realises that he cannot leave his men. Lorene leaves for the mainland, accompanied by Karen.