In a post-drought USA, where the struggle for water can lead to violence, Ernest Holm lives a simple life with his children, Jerome and Mary. Despite most of the community leaving, Ernest remains in their small house and field, holding on to the hope that the land will thrive again with proper irrigation. To sustain his family, he trades supplies with those known as the water people, who extract precious water from deep wells.
When tragedy strikes and his mule breaks its legs, forcing him to euthanize it, Ernest buys a robotic carrier machine at an auction, outbidding Flem, a young man who has been courting Mary without parental approval. Ignoring Flem's proposal to rent the machine, Ernest is soon faced with further challenges. One fateful morning, he discovers that his new machine has vanished. In a desperate search, he confronts the water people and is wrongfully accused of theft. After a fierce altercation with their leader, Caleb, Ernest claims his knife as a trophy of victory.
Undeterred, Ernest tracks down his machine, only to find Flem using it to transport a supply of water. In a confrontation, Flem, determined to pursue his smuggling endeavors, resorts to violence, ultimately leading to Ernest’s death by throwing a bottle at him. Time passes, and although Ernest is buried, the robotic machine mysteriously goes missing.
Meanwhile, Flem marries Mary after assisting with the construction of an irrigation system that secures their farm's future. However, the damaged machine, now lost and wandering, has a default command directing it towards a nearby store. The store owner informs Jerome about the machine, setting off a chain of events that leads Jerome to discover its laser sensor can record video.
Curiosity piqued, Jerome watches the recording and uncovers the shocking truth about Flem and Ernest’s demise. Before Flem returns home, Jerome confronts him, probing for answers about how the machine navigated back. Flem’s deceit only fuels Jerome’s anger, yet he chooses not to act immediately.
As fate would have it, Flem suffers an accident during a supply run, tumbling into a pit and breaking his legs while calling for help. Jerome, who has been shadowing Flem, arrives at the pit’s edge. Realizing that Jerome knows the truth about his father’s fate, Flem attempts to negotiate for mercy. In a moment of reckoning, Jerome ends Flem’s life, opting to keep the truth about Ernest intertwined with secrets, choosing to protect Mary from the darkness of their shared past.
