THEY DIED WITH THEIR BOOTS ON

The film follows the life of George Armstrong Custer (Errol Flynn) from attending West Point, wooing of Elizabeth "Libby" Bacon (Olivia de Havilland) who becomes his loving wife, the American Civil War, and the Battle of Little Big Horn.

Custer enters West Point and quickly establishes himself as a troublemaker, after showing up in an outfit he designed himself that made him appear as a visiting officer. After he is almost kicked out of West Point for the misunderstanding, he signs up as a cadet, and stacks up demerits for pranks, unruliness, and disregarding the rules. Although he does not graduate with the rest of his class, he is given an officer position with the Union Army when the Civil War breaks out, at the reluctance of most of his supervisors. They ultimately decide that his impetuousness will be valuable in an officer, and he is given his orders to report to Washington, D.C.

Custer's relationship with Libby Bacon begins at West Point, when he is walking a punishment tour around the campus. On punishment, he is not allowed to talk, but he is approached by Libby who is looking for directions. As soon as his punishment is over, he runs after her, and tells her he will meet her at her front porch that evening. Because of his orders to travel to Washington, D.C., Custer misses his meeting with her.

Once in Washington D.C., Custer befriends General Winfield Scott (Sydney Greenstreet) who aids him in being placed with the 2nd Cavalry. He becomes a war hero after disregarding his superiors' orders in a crucial battle and successfully defending a bridge for the infantry to cross. He is awarded a medal while recovering in hospital after a shot to the shoulder.

Upon returning home to Monroe, Michigan, as a hero, Custer marries Libby and they set up a house together. However, Custer is bored with civilian life and has begun to drink. Libby visits Custer's friend General Scott and asks him to assign Custer to a regiment again. He agrees, and Custer is given orders to go to the Dakota Territory, where he will ultimately be involved in Custer's Last Stand.

When Custer and Libby arrive in the Dakota Territory, Custer finds the soldiers he is supposed to lead are drunken, rowdy good-for-nothings. An old enemy from West Point, Ned Sharp (Arthur Kennedy), is running the bar in town, as well as the General Store which is providing firearms to the local Native Americans. Furious, Custer shuts down the bar and teaches his troops a song, Garry Owen, which brings them all together. He whips them into shape in time for an inspection by the General. However, Sharp gives the troops each a bottle of liquor right before they are supposed to report, and they embarrass Custer by riding past the General drunk. Custer is relieved of his post and sent home.

On the train home, Custer hears from Libby that Sharp is trying to start a gold rush in the Black Hills of the Dakota Territory, the Native Americans' sacred land. A gold rush would bring lots of business to Sharp's shipping line. Outraged, Custer takes the information to Congress, but they ridicule him. When news arrives that the presence of gold miners has led to open conflict between Native Americans and American troops, Custer returns to the Dakota Territory with Libby to help his battalion.

On the day of Custer's last stand, Custer realizes that a group of infantry will march into a valley where thousands of Native Americans stand ready to fight them. Knowing the infantry won't have a chance, he says a tearful goodbye to Libby and leads his battalion into the battle to save the infantry. Arrows fly and horses trample across the valley, and all are killed, including Sharp, who had elected to ride with the regiment to, as Custer puts it, "Death or Glory. It depends on one's point of view", and who admits with his last breath that Custer may have been right about glory and money when he said that "At least you can take it [glory] with you". Custer himself is finally downed by a gunshot from Crazy Horse (Anthony Quinn) himself.

In the film, the battle is blamed on unscrupulous corporations and politicians craving the land of Crazy Horse and his people.

Custer is portrayed as a fun-loving, dashing figure who chooses honor and glory over money and corruption. Though his "Last Stand" is probably treated as more significant and dramatic than it may have actually been, Custer (Flynn) follows through on his promise to teach his men "to endure and die with their boots on." In the movie's version of Custer's story, a few corrupt white politicians goad the Western tribes into war, threatening the survival of all white settlers in the West. Custer and his men give their lives at Little Bighorn to delay the Indians and prevent this slaughter. A letter left behind by Custer absolves the Indians of all responsibility