Capt. Tom Reynolds (Frank Sinatra), a charismatic guerrilla fighter, heads a combined British and American force assigned to repel Japanese invaders in Burma during World War II while training the Kachin natives in his style of warfare. During quieter moments, he finds time to romance Carla Vesari (Gina Lollabrigida), the voluptuous paramour of enigmatic local businessman Nikko Regas (Paul Henreid). Dispensing with the niceties of seduction, Reynolds explains to his conquest, "I kissed you, you kissed me back. I got the message." Although ordered to remain in Burma, Reynolds gets annoyed when his Kachin friends are attacked by Chinese nationalists commanded by Chiang Kai-shek. Defying orders, he leads his guerrilla unit over the border into China for some particularly brutal payback. As a result, he will have to deal with legal retribution, possibly a court-martial, upon his return. Meanwhile, Carla must decide whether to stay with Regas or leave for a new life in the U.S. with Reynolds.