In 1900 Texas, Claude "Sweet Tooth" Barbee, Frank "Blockey" Jackson, and Tom Nixon ambush a chain gang to free their fellow member, Slap Jack Davis. Davis knows where the gold from their last robbery lies, but the others are dismayed when it turns out to be 500 miles away. Nixon, their leader, balks at the journey, but the others threaten to go without him. On the way, they meet a traveling salesman and his ward, a teenager who operates a ventriloquist's dummy. Amused by the puppet, the men pause to listen to their pitch, only to become enraged when the salesman beats the boy. After killing the salesman, Barbee accepts the boy, Willie, into their gang. They are joined shortly by Goody Spotswood, their scout. As they pass through a town, the gang kills several people while robbing a local church, and Davis is wounded.
Meanwhile, Rudy Goebel murders his employer. When his wife protests, he kills her, too. As he dumps his wife's body in the cellar, he chastises his children for an unspecified transgression. The Nixon gang barges into the house seeking aid; all but Barbee eat Goebel's drugged soup. Goebel tortures Davis, but Barbee wakes and kills Goebel. The gang leaves at dawn. The next time they camp, they wake to find Nixon dead. They blame each other for his death, but Barbee insists Nixon died of natural causes.
Barbee becomes the de facto leader, and the gang robs several towns on their way toward the gold. Sheriff Everheart and Deputy Marshall Peak chase after them, enticed by rewards and the thought of being hailed as heroes. The Barbee gang takes refuge at the Wilberforce homestead, where Jackson rapes and murders the Wilberforces' daughter. Barbee reluctantly kills her vengeful father but stops the gang from killing the other family members. They flee after stealing a horse from the Wilberforce barn and finding one of their horses slaughtered.
After they rob a whorehouse, Pearl Nava follows after them, asking to join. As she and Barbee become closer, he tells her about the gold. They have sex at a hotel where Everheart and Peak are staying, and Barbee leaves a taunting note for them. When Barbee wakes, Pearl and the map to the gold are gone, and Willie is dead. The others blame Pearl, but Barbee reasons Pearl is no murderer; instead, he suggests a crazed native American is responsible. Spotswood dies next, and Barbee is haunted by nightmares of a bestial man who hunts his gang.
While Davis seeks aid from a doctor, Pearl tips off Everheart. Barbee, Davis, and Jackson come upon a man who is attacking a woman. Satisfied this is Spotswood's killer, they kill him. When they set up camp, Jackson wanders off. As Barbee and Davis find Jackson's mutilated body, Everheart and Peak catch up to them. Peak is killed in the resulting shootout, and Davis is further wounded. Everheart chases Barbee and Davis to a barn, intending to smoke them out, but Barbee kills Everheart. Convinced his wounds are fatal, Davis reveals that the gold is at the bottom of a well. That night, Barbee dreams of the bestial man, and wakes to find that Davis' throat has been slit. At Davis' request, Barbee mercy-kills Davis as he slowly bleeds to death.
Barbee pretends to shoot himself in grief. When the killer reveals himself, Barbee is surprised to find it is one of Goebel's sons. After killing the boy, Barbee reaches the well. There, he is wounded by a bounty hunter, whom he kills. Barbee collects the gold, only to be attacked by Goebel's other son, a twin. The boy pushes the wounded Barbee into the deep well, where he finds Pearl's corpse at the bottom. The boy walks off, ignoring Barbee's cries.
