Jeremy Barnes wishes things were different in her life, but she doesn't feel like she has the power to change anything. Her husband Wilfred scrapes by as a mediocre cattle broker, she is regularly harassed by the town bully McCanles, and she doesn't fit in with the rough people who live in the lawless town of Julesburg.
McCanles shows up in the Barnes' office with over 200 head of cattle to sell. Wilfred eagerly takes on the commission, but Jeremy doubts that McCanles acquired the herd legally. The two argue over the deal and Wilfred leaves for the bank to make arrangements.
Later, a boy named Tommy wanders into the office from the hotel lobby, fascinated by Jeremy's typewriter. Jeremy obliges him by typing out the boy's name on a piece of paper. They are interrupted by a tall, dark-haired cattle buyer who inquires about a recent cattle sale, but Jeremy refuses to divulge details to him. When a man claiming to be Tommy's brother comes in to fetch him, the boy bursts into tears.
Worried about Tommy, Jeremy brings some warm milk and a sandwich to his hotel room. Tommy reveals that his real brother was killed. Just then, another man hiding in the room steps out, the cattle buyer she met earlier named Cheyenne Bodie. He tells her that the cattle her husband is buying are stolen and appeals to her sense of decency to do the right thing. Jeremy claims to be powerless in the situation and leaves.
Downstairs, McCanles and Wilfred are celebrating the pending sale of the cattle. Jeremy enters and tells them that the bill of sale is missing, without which the deal won't go through. McCanles gets angry and manhandles Jeremy. Her husband tries to intervene, but McCanles roughs him up. Jeremy begs the man to leave them alone when Cheyenne appears and orders McCanles to quit harassing the Barnes. He tells Wilfred to take Jeremy home and they leave. Behind them, the hotel lobby erupts in gunfire.
The next morning Jeremy and Wilfred return to the hotel office to collect their things. McCanles meets them (he and his men are still waiting for Cheyenne to come down from the hotel's second floor) and demands his money. He is interrupted when Tommy and Smitty (the man pretending to be Tommy's brother) come down the stairs under a flag of truce. Smitty fools McCanles and his men into emptying their guns and he and Cheyenne cover them. Another one of McCanles' goons shows up and a battle ensues. Wilfred mans up and gets into the fight as Jeremy watches, hunkered in the office with Tommy. Wilfred shoots and kills the menacing McCanles while Smitty and Cheyenne take care of the others.
Peace has come to Julesburg. Jeremy is going to take a guardian role over Tommy until they can contact his relatives. She gives Cheyenne a goodbye kiss and a goodbye handshake to Smitty.