In 1906, Alipang (Tetsu Komai) and his Muslim Moro people guerrillas are terrorizing the people of the Philippine island of Mindanao, raiding villages, killing the men, and carrying off the women and children for slaves. Instead of maintaining garrisons indefinitely to protect the Filipinos, the U.S. army tests out a new tactic at Fort Mysang. The army detachment is replaced by a handful of officers – Colonel Hatch (Roy Gordon), Captains Manning (Russell Hicks (actor)) and Hartley (Reginald Owen), and Lieutenants McCool (David Niven) and Larsen (Broderick Crawford) – who are to train the native Philippine Constabulary to take over the burden. Army doctor Lieutenant Canavan (Gary Cooper) is sent along to keep them healthy. They are welcomed by a skeptical Padre Rafael (Charles Waldron).