The story is presented as a flashback of Max Eriksson, a Vietnam veteran. A platoon of American soldiers is on patrol when they are suddenly attacked by the Viet Cong. While on flank security, the ground cracks under Eriksson as he is above a Viet Cong tunnel. Sergeant Tony Meserve pulls Eriksson out of the hole and eventually, the Americans stave off the attack.
The platoon takes a break outside a river village in the Central Highlands. While relaxing and joking around, one of the platoon members, Specialist 4 "Brownie" Brown, is killed when the Viet Cong ambushes them. Shortly afterward, Private First Class Antonio Diaz arrives as Brownie's replacement.
Frustrated because his squad has been denied leave for an extended period, Meserve orders the squad to kidnap a Vietnamese girl, Than Thi Oanh, to be their sex slave. Eriksson strenuously objects, but Meserve silences him and ostracizes him from the rest of the squad, later threatening to kill Eriksson if he dares an attempt to interfere. The girl is forcibly taken to the squad's next command post and is repeatedly beaten and raped by all the men but Eriksson.
The squad later takes up a position near a railroad bridge overlooking a Viet Cong river supply depot. Meserve has Diaz order air support for an assault on the depot, then orders Oanh to be killed. Before the squad can kill her, Eriksson fires his rifle into the air, exposing them to the nearby Viet Cong. In the midst of the firefight, Oanh tries to escape. Eriksson tries to save her but is stopped by Meserve, who knocks Eriksson down with the butt of his gun. Eriksson watches helplessly as the entire squad shoots Oanh numerous times until she falls off the bridge.
After the battle, Eriksson wakes up in a hospital. He jeopardizes both his life and military career (thanks in large part to indifferent superiors, who prefer to bury the matter) to expose the crime. Eventually, an attempt on Eriksson's life is made by Corporal Thomas E. Clark, who tries to kill Eriksson while he is using the latrine. Eriksson takes action by confronting Meserve and his men, and using a shovel, strikes Clark across the face, scaring the rest of the men.
Eriksson then meets a chaplain at the bar and tells him the story of the girl. There is an investigation and the four men who participated in the rape and murder are court martialed: Meserve receives ten years hard labor and a dishonorable discharge, Clark is sentenced to life in prison, Private First Class Herbert Hatcher receives fifteen years hard labor, Diaz receives eight years hard labor.
At the end of the film, Eriksson wakens from a nightmare to find himself on a J-Church transit line in San Francisco, just a few seats from a Vietnamese-American student who resembles Oanh (same actress). She disembarks at Dolores Park and forgets her scarf, and Eriksson runs after her to return it. As she thanks him and turns away, he calls after her in Vietnamese. She surmises that she reminds him of someone, and adds that he's had a bad dream. They go their separate ways and Eriksson is somewhat comforted.
Who is the replacement for Brownie after he dies?
Antonio Diaz