In 1859, after the plantation on which Shields "Emperor" Green works in Charleston, South Carolina, is gambled away by his master, a cruel new overseer tortures Shields and whips his son Tommy. In retaliation, Shields kills the overseer and flees. Shields' wife Sarah is killed during his escape.
Shields evades capture on his way north and learns that a bounty has been placed on his head. His master and neighboring plantation owners hire bounty hunter Luke McCabe to catch him. Shields is found by Truesdale, who gives him refuge in his house despite his wife Delores' objection; however, the next day, Truesdale turns on him and forces Shields to lock himself in a cage, revealing his intention to wait for the bounty hunters to capture Shields for the reward money. Delores kills Truesdale and frees Shields, who takes the responsibility for the latter's murder.
Shields meets up with a young bank robber, Rufus Little. McCabe and his men pursue them and almost catch them, and Little dies from the injuries in the process. Shields takes his gun and looted money and meets up with Levi Coffin (a real Quaker abolitionist) at his cabin. There, he gives him the money to buy his son's freedom. After McCabe appears, Shields heads to Maryland where meets John Brown and Frederick Douglass, who is preparing the raid at the Harpers Ferry. Shields agrees to join them to fight for the end of the slavery.
Shields, Brown and his men take over Harper's Ferry. United States Army Colonel Robert E. Lee and his forces retake it and most of Brown's men suffer casualties. As Shields rides away on a horse, McCabe shoots and wounds him. Shields takes refuge at a church, but McCabe and his men track him down. During a gun battle. Shields climbs to the spire, pursued by McCabe, and blows it up as he leaps into a river to make his escape. Coffin buys Tommy's freedom and takes him to Shields.
In 1890, his son writes a book about him and takes it to a publisher.