Cecil B. DeMille directed this romanticized version of Calamity Jane and Wild Bill Hickok stopping the selling of rifles to Indians.
President Lincoln urges war veterans to go west and make the frontier safe. A gun-maker proposes trading rifles to Indians, and John Lattimer (Charles Bickford) distributes them from St. Louis labeled "farming tools." Bill Hickok (Gary Cooper) finds Buffalo Bill Cody (James Ellison) is married and asks if he is tamed. Louisa Cody (Helen Burgess) tells Hickok that Cody is going to run a hotel. Hickok catches a gambler cheating. Calamity Jane (Jean Arthur) kisses Hickok, and they quarrel. Calamity drives a stagecoach to Hays City. Hickok finds Breezy wounded and tells General Custer (John Miljan) to reinforce the fort. Cody goes as a scout despite Louisa's objections. Louisa gives Calamity a dress and asks her to stay with her. Calamity sees Indians and sends Louisa to town. Calamity offers the Cheyenne gifts, but they capture her. Hickok tries to buy Calamity with his musical watch and guns; but both are taken prisoners to Chief Yellowhand (Paul Harvey). The Cheyenne open crates of rifles, and Yellowhand says that the white men take their land and buffalo; he demands to know where the soldiers are going. Hickok tells Calamity he loves her, and she informs them in order to save his life. When the Cheyenne find the troops, she and Hickok are freed. During the battle Hickok jumps an Indian and gives Calamity his horse and rifle to ride to Custer, while he joins the soldiers. Cody is wounded in the head.
Custer tells Calamity he would like to shoot her but can't. After six days the troops are tense. The Indians attack, and Hickok gets his watch and guns back. Custer arrives with the cavalry. In town Calamity uses a whip to keep away irate men. Hickok looks for the man who sold the rifles. Three soldiers tell Lattimer about gold in the Black Hills, and Jack McCall (Porter Hall) warns Lattimer. Hickok challenges Lattimer to meet him with a gun. A soldier shoots Hickok, and he kills the three soldiers in the gunfight. Louisa calls Hickok a murderer but treats his wounded arm. Calamity tells Hickok that Custer wants him dead or alive, and Lattimer left town.
After six weeks Cody finds Hickok, both walking. Cody says that Custer sent him to bring him back. They learn from an Indian that Custer was killed and that Cheyenne are going to join Sitting Bull. Calamity tends bar in Deadwood, and McCall says he wants to be a big man. Hickok finds Calamity, and McCall tells Lattimer that Hickok is in town. Hickok gives Calamity his watch, and then he makes Lattimer show him his cargo. Lattimer pulls his gun, and Hickok kills him. He orders Lattimer's men into the saloon to wait for the army to get the rifles. They play poker, and McCall shoots Hickok from behind. Cody and the cavalry arrive to arrest the men. Calamity cries, and Cody says he will remember Hickok.
An illustrious lawman in Hays City and Abilene, Hickok did eventually marry Agnes Lake. The plot of selling rifles to Indians is apparently a fabrication used to glamorize him as a hero. He was murdered in 1876 by Jack McCall, who was hanged for it five months later.