As the movie opens, soldiers are already fighting in the A Shau Valley, but it's too hot of a fight and they withdraw to base camp. The soldiers dig trenches and prepare for battle. They mostly dream of girls, visit whorehouses, and think of home. New soldiers are ordered to brush their teeth and keep up good hygiene. The soldiers get very little sleep and do not want to return to the A Shau.

The camp is mortared. Women and children are in the middle of the fight, and some are killed. Doc finds a headless soldier without dog tags. There is great tension between the soldiers. Doc and Langwilli get into a fight at the whorehouse over why the African Americans were sent to Vietnam.

On the 10th of May, the troops are sent back to the valley. They are attacked in the jungle, and Danvers, a black soldier, is killed. On May 11th, the soldiers begin the assault on Hill 937. The going is brutal. Air support saves them by bombing the North Vietnamese. Later the soldiers suffer through a miserable, rainy night. They could be killed at any time.

The next morning the soldiers try the hill again. A North Vietnamese dressed in a U.S. uniform attacks Gaigin but was killed. Airplanes drop Willie Pete and napalm but the enemy is covered in bunkers. American gunners in helicopters accidentally shoot their own men. (When this happened in the real attack on Hamburger Hill, the battalion commander, Lt. Colonel Honeycutt, sent a message to the division staff. "I want you to make sure that everybody gets this. And I mean the artillery people and the gunship pilots and the liaison officers . . everybody. I don't want ..(them) .. out here if they can't shoot the enemy instead of us. I'm tired of taking more casualties from friendlies than from the enemy. The next goddamn sonofabitch who comes out here and shoots us up, we're gonna shoot his ******' ass down. And that's final. Now you go back and tell 'em that.")

By May 16th, they are part way up the hill and try another attack but are stopped short of getting to the top. On May 17th, they try again but are again unsuccessful. TV reporters show up. The reporter says that Senator Kennedy thinks they'll never be able to take Hamburger Hill. Frantz tells them that they have not even earned the right to be there, let alone criticize.

On the 18th of May, the soldiers were close but the rain and mud kept them from getting to the top. Gaigin dies. Doc is shot and is almost saved, but he dies before the MedEvac helicopter makes it to him.

On May 20th, the soldiers try again. Lt. Eden loses his arm without realizing he has been hit. Worcester gets blown up and dies. Motown falls in a Vietnamese trap and dies, and Bienstock is killed. Langwilli gets bayoneted in the back and dies. Frantz, Beletsky, and Washburn are first to make it to the top. The hill was secured on May 20th, 1969.

It took three US Army battalions with ARVN support to take Hamburger Hill. The defenders, the 28th North Vietnamese Regiment, were nearly wiped out.

About one month later the 101st left the A Shau valley, and the North Vietnamese were free to use Hill 937 once again. Critics charged that the battle wasted American lives and exemplified the irrelevance of U.S. tactics in Vietnam. Defending the operation, the Division commander of the 101st acknowledged that the hill's only significance was that the enemy occupied it.   "My mission," he said, "was to destroy enemy forces and installations. We found the enemy on Hill 937, and that is where we fought them."