During the Civil War, brothers Jesse and Frank James, Cole and James Younger and Kit Dalton ride into Lawrence, Kansas and are immediately accused of being members of the notorious band of guerrilla fighters known as Quantrill's Raiders. They are sentenced to hang, but the lynching is stopped by Union soldiers. After the men deny any association with the band's leader, William Clark Quantrill, the Union captain releases them with a warning against Quantrill. Later, however, they arrive at Quantrill's camp, where they witness a mock trial of captured Yankee soldiers. Despite the soldier's request to be treated as prisoners of war, Quantrill kills them. Tate, one of Quantrill's men, taunts Jesse about his youth. During the ensuing knife fight, Jesse unnecessarily kills Tate, who unknown to the others, is a Union spy. Impressed, Quantrill makes Jesse his right-hand man. Later, Kate Clarke, Quantrill's disillusioned lover, accuses Quantrill of having become a blood-thirsty murderer. The next day, when Jesse tells Kate that he and the others came to Quantrill after the murder of their families by Union soldiers, Kate points out that Quantrill is also a killer. The truth of her statement becomes apparent during a deadly raid on a nearby farmhouse. Jesse is upset by Quantrill's indiscriminate killing and looting and decides to leave the Raiders. Although Kate suggests that they leave together, Jesse changes his mind after Quantrill justifies his actions and promises an end to the killing. During the next, brutal raid on Lawrence, in which women, children and other civilians are killed, Jesse sees that nothing has changed. With no other alternatives, however, Jesse keeps riding with Quantrill. Others do leave the group, but Jesse and Frank, the Youngers and Dalton all stick with Quantrill. During an attack on Quantrill's hideout by Union soldiers, Quantrill is blinded and Jesse assumes command. The soldiers give the remaining Raiders until daylight to turn over Quantrill. That night, one by one, the men and Kate escape out the back, while Jesse stays behind with Quantrill. When Jesse refuses to leave Quantrill, despite his orders, Quantrill pushes him out the door and then walks out the front to face the Union solders. After Quantrill is shot down, Kate leaves Jesse, who rides out to join his friends in a life of crime.