Isolated on a South Pacific island in World War II, a Japanese platoon with no radio equipment is joined by American marines whose plane crash-lands on the island. The marines' radio also is damaged. The two groups discover each other's presence on the island, and fighting breaks out between them. The Japanese control a freshwater spring the marines want to use; and when one of his men is seriously injured in the leg, Lieutenant Kuroki, in charge of the Japanese platoon, trades water, fish, and potatoes to the marines for the services of Chief Pharmacist's Mate Maloney, who successfully amputates the man's leg and thereby saves his life. A truce is arranged between the two factions with the condition that if either side again becomes part of the war, fighting will be resumed. All is peaceful until an incident sets the two groups in preparation to fight again, but a typhoon diverts attention to the need to save the water supply. The Americans' radio is repaired, and they learn that a U. S. ship is on the way. Captain Bourke, the marine leader, offers Lieutenant Kuroki surrender terms, but he refuses them because of the conditions of their original agreement. The warship arrives, and fighting resumes. All the Japanese are killed, and only five marines, including Bourke and Maloney, survive. Kuroki leaves his journal for Bourke to deliver to his widow.