In a post-drought apocalypse United States, people kill for water. Ernest Holm lives with his son Jerome and daughter Mary in their small townhouse and field. His wife has been involved in an accident earlier and is now permanently hospitalized in a facility where she can walk while wired to a special frame. While everyone else has left the area, Ernest and his family remain, as Ernest believes that the land will grow once more if only there is irrigation. Ernest gets water for his family by delivering supplies to the “water men” who extract water from deep wells through a government deal. When his mule breaks its legs and he has to kill it, Ernest goes to Sam Lever’s auction house and buys a robotic carrier machine called Simulit Shadow (“Sim”) to replace it, beating the offers of Flem Lever, Sam’s son, a young, troubled man who has been seeing Mary without Ernest’s consent.
One morning, Ernest finds the Sim is missing, and he goes looking for it. When he gets to the water men, he is accused of stealing their supplies. He finds Flem transporting the stolen supplies with the Sim; Flem plans to sell them at the border. Ernest takes Flem captive, ties him to the machine, and aims to take the supplies back to the water men. When they stop due to dehydration, Flem convinces Ernest to rehydrate with the liquor they are transporting. Wanting to escape, Flem throws a stone at Ernest’s head and frames the machine for Ernest’s death.
Flem marries Mary after helping the family obtain illegal irrigation from the water men, thus saving their farm, which was originally Flem’s father’s. But after finding out Ernest had overwhelming debts to repay to a bank, which is now going to repossess the farm, Flem tricks his friend Robbie into selling his baby behind his wife’s back. Robbie is killed and the Sim is lost in an altercation with the buyers. However, the machine returns limping and mangled to its manufacturer, who resides in a city across the border. The owner, Calvin Hooyman, reaches Jerome at the Holm residence via CB radio, informing him about the machine.
Jerome crosses the border with the help of Anna, a girl who lives with the “settlers”, people fighting back against the government’s regulations and considered terrorists. Jerome meets Calvin, who gives the repaired Sim back to him, and shows Jerome how the machine’s laser sensor behaves like a rudimentary video recorder. Jerome plays the recording and finds the truth about Ernest’s death. Arriving home before Flem, Jerome questions him as to how the machine found its way home, since Flem claimed to have sold it in order to repay the debt. Flem’s lies only infuriate Jerome more, but at first he takes no action. Instead, he lures Flem out in the desert by posing as Robbie via radio and letters, ultimately causing Flem to fall into a pit trap and break his legs. As Flem cries for help, Jerome, who has been secretly following him, comes at the pit’s mouth. Flem realizes that Jerome knows about what happened to Ernest. He tries to elicit Jerome’s mercy, but Jerome coldly shoots him in the head. Jerome ultimately decides to withhold these events and the circumstances of Ernest’s death from Mary, who is pregnant with Flem’s child. Brother and sister remain in the house, planning to bring their mother there from the hospital now that they can pay for her brace wires, and wishing the baby will be a girl.
The film is divided into three chapters, named after the main character in each of them: “Ernest Holm”, “Flem Lever”, and “Jerome Holm”, respectively.