In the future, the USA has been ravaged by a severe drought and people are now willing to kill for water. Most of the people have left, but the Holm family stays because the father Ernest thinks plants will grow again if they could get some water. He remembers when the land was green, but his son Jerome doesn’t.
One day, two thieves try to break into a small building in Ernest’s farm by burning down the lock. Ernest catches them red-handed and opens fire, causing one of the thieves to try to shoot back. He immediately gets killed, and the second thief asks for mercy as he explains someone told him there was water there.
He also claims he needs to pee and reaches for his pants, but Ernest sees the gun and shoots him first. Jerome sees all this from afar and claims he could’ve helped, but Ernest just tells him to call him “dad” instead of his first name. Then Ernest unlocks the small building, revealing a pump.
Unfortunately it doesn’t give them any water, so they’ll have to force their mule to keep going without drinking. The duo keeps going and meets the "watermen", a group of people who hold a monopoly to distribute water extracted from deep wells through a government deal. Ernest gives them supplies and the men pay him with water.
He also reminds Jerome not to anger these guys because they’re dangerous - they must only do the trading and quickly leave. Ernest often tries to convince them to provide water for his farm, but the watermen charge too much. On their way home, their mule falls and gets severely wounded.
Since the animal is in pain, Ernest shoots it to end its suffering. Jerome cries yet swears he could’ve done it. When they finally arrive at the farm, Jerome’s sister Mary serves them MREs.
Then she scrubs the dishes with soil while Ernest listens to the radio and Jerome sketches animals, which are their only hobbies. Suddenly Ernest hears a noise and rushes outside to discover Mary has sneaked out the window to meet with her secret boyfriend. The next day, Jerome and Ernest go to Sam’s auction house and bid on a robot known as Simulit Shadow or Sim to replace their mule.
Sam’s son Flem bids as well and fights them to the very end, but Ernest wins the auction and his debt gets worse. Afterward they go to the hospital to visit the kids' mom Katherine, who can’t walk because she was in an accident. The hospital has a special machine that connects her to a wire to help her walk, and the only way for the family to get Katherine home would be buying that expensive machine.
After a lovely afternoon with Katherine, the duo goes home. On the road, they see Robbie and Sooz with their baby. Ernest calls them vultures for using their kid as a pity card to get handouts and drives away to ignore them.
They get to the gas station and after filling the tank, Ernest drinks a bit to round up the price. Then he takes some water back to Robbie and his family. The couple has been thinking about selling the baby because they can’t afford to raise him, but Ernest advises them against it and promises to help them with the water.
Later at the farm, Flem shows up at the farm, revealing to be Mary’s secret boyfriend. He asks to borrow Sim and promises to pay a rent fee, but Ernest refuses unless Sam signs a guarantee. Flem gets offended and tells Ernest he’ll never irrigate this land before leaving.
The next time Jerome and Ernest meet the watermen, they make good time thanks to Sim and Ernest starts talking the guys into considering an offer for putting a water line in his farm. Afterward Ernest starts digging out his old pump so that the watermen can check what they have. While working he tells Jerome he needs to get out there and meet a girl or at least make some friends, but Jerome would rather take care of his family.
On their way home, they see Flem drive by at great speed. At the farm, Mary washes the clothes by putting a cleaning agent in the vacuum cleaner. Ernest arrives and forbids her from going out anymore, causing Mary to lash out and says she’s old enough to do whatever she wants.
As Ernest swears he only wants to protect her, Mary says he hates her dad and loves Flem, then she tries to run away. She bumps into Jerome and asks him for money, giving Ernest time to catch up to her and stop her. Mary cries as she claims Ernest failed their family, then he locks her up and nails her window shut.
Sometime later, Ernest and Jerome wake up to discover Sim has been stolen. Ernest assumes it was Flem and goes to his house, but he learns from Sam that Flem left on a truck that morning for the mountains. It’s revealed that Ernest’s farm used to belong to Sam and Flem is obsessed with what his family has lost, even though Sam thinks that land is infertile and water won’t help.
Afterward Ernest goes to the mountains to investigate and he’s suddenly knocked out. In the evening, Ernest wakes up at the watermen’s camp, where he’s accused of having stolen their supplies using Sim. Ernest insists that he didn’t do it but the leader Caleb attacks him.
A fight ensues and after lots of struggle, Ernest manages to steal Caleb’s knife and a rifle, which he shoots in the air to keep everyone back. He runs away while Caleb continues to yell threats at him. On his way home, Ernest finds Flem sleeping by the fire and Sim nearby.
He stole the machine and the supplies to make Ernest look bad. Earnest waits until morning to wake him up with the rifle on his face, then he ties Flem to Sim, who is carrying the supplies. As they walk under the hot sun to find the watermen, Flem keeps taunting Ernest by talking about Mary, so Ernest pulls the rope to make him fall as punishment.
Eventually they’re both too thirsty to survive for long and Flem convinces Ernest to stop for a drink. The supplies have alcohol, not water, and soon Ernest is getting drunk because of his addiction. Flem only pretends to drink while he claims that Caleb wants his head so he only stole the machine to survive.
He even offers Ernest money, but he turns it down because the story is suspicious. Then Ernest tries standing up, but the alcohol makes him dizzy and he can barely move. This was Flem’s plan all along and he uses the chance to hit Ernest with a rock, causing him to hit his head on the cliff.
As he bleeds and falls unconscious, Ernest has a flashback of Katherine’s car accident, which had been caused by his drinking habits. Later when Ernest wakes up, he’s tied to Sim and Flem starts pouring more alcohol into his mouth, screaming like a maniac. Afterward Flem goes to the farm and Mary jumps on his bike so they can escape together.
Getting worried about Ernest, Jerome decides to go looking for him. By the time night falls, he finds Sim at the watermen’s camp, where the guys tell him that his dad died because of an accident with the machine. When it’s time for the funeral, Mary comes back and the siblings cry together.
They also have to visit their mom to give them the bad news. Flem picks them up in his truck and takes them home. At the farm, a furious Jerome starts hitting Sim with a hammer, so Flem comes to stop him.
He explains grief is hard but he can’t let it ruin a source of income and offers to become the new head of the family so he can help the siblings. He also shocks Jerome by announcing Mary is pregnant. Flem has big plans in mind for the farm, and Jerome agrees to let him try.
In the afternoon, Flem takes supplies to the watermen and asks Caleb to put a water pipe on the farm. At first Caleb refuses, but suddenly Flem blames him for Ernest’s death since Caleb’s rifle and knife were found with the body. Scared of the possible consequences, Caleb agrees to divert water to the siblings’ land.
A few days later, the new farm pump is officially installed and Flem works very hard all day long to plant and grow wheat, which is watered by sprinklers. The family now can also enjoy actual showers. Some weeks later, Jerome is surprised to see a little leaf on the ground, and eventually the land is covered in wonderful plants.
To celebrate, Flem and Mary get married and tattoo each other’s initials on their hands. During the party, Flem drinks and keeps thinking about Ernest’s death. A couple of days pass and Sam shows up at the farm with two men from the bank.
It turns out Ernest’s debt is huge and they want Flem to pay it. Flem scares the horses with his bike just to look tough and Sam scolds him, explaining that nobody ever wanted to buy the land and Ernest had it because he simply never moved off. Thanks to the water and the crops, the bank will be able to sell it, so Flem must pay if he doesn’t want to lose it That night, Flem puts Sim on his truck and picks up Robbie with his baby.
He pretends they’ll be asking around for some prices just to get an idea, only for Flem to sell the baby against Robbie’s will. Freaking out, Robbie asks for his baby back and the buyers open fire, killing Robbie. They try firing at Flem too, who shoots back as he runs away, leaving the machine behind.
Sim is caught in the exchange and the damage makes it activate a mode that guides it back to the original factory. The next day, Flem pays the bank with the baby money, but he tells the siblings that he sold Sim to Robbie. Meanwhile Sim makes it to the city and is found by its builder Calvin, who finds the owner’s information and calls the farm.
Jerome picks up the call and starts getting suspicious, so he runs to the local market. He discovers Flem talking to Sooz, who is keeping a doll in her arms pretending it’s her baby. Noticing this, Jerome tries talking to them but Flem quickly takes Sooz away.
Later at the farm, Jerome asks Flem about Robbie, but Flem says Robbie took Sim and abandoned his family. Determined to discover the truth, Jerome announces he’ll visit his mother, but he actually takes a bus to the border. However the guards don’t let him pass because he’s a minor without a guardian.
At that moment he’s approached by Anna, who offers to cross him over if he pays. Jerome agrees and Anna puts him in a truck full of chickens. In just a couple of hours, the truck reaches the city and Jerome sees it for the first time.
He reunites with Anna and she takes him to the factory, but she only takes half the money as payment. She explains that the round trip is a scam, he doesn’t need a guide to go back because nobody will stop him from leaving. Before she leaves, Jerome asks if she ever met a guy named Ernest, but Anna doesn’t recognize the name.
Afterward Jerome meets with Calvin, who shows him all the functions of the machine. It turns out Sim’s eyes are cameras that were made to capture the slope for reforestation and have recorded everything Sim has seen. Calvin teaches Jerome how to use it and gives him some privacy.
Jerome gets emotional when he sees his dad again, but this transforms into horror when he learns that Flem killed Ernest. It turns out Flem tied Ernest to the machine and sent it in the direction of the watermen’s camp, making it look like Sim had lost control and dragged Ernest to his death by accident. Jerome has a breakdown in the middle of the office.
In the evening, it starts raining over the farm for the first time in over a decade. Jerome soon returns and plays it cool, asking Flem how he got Sim back. Flem is confused and checks the barn, shocked to see Sim standing there with no damage.
He says Robbie must’ve brought it back out of guilt. A few days later Jerome visits Katherine for real and promises to take care of her like Ernest did. One afternoon, Flem and Jerome are hunting animals to keep them away from the crops.
Flem fails all his shots and passes the rifle to Jerome, blaming the weapon for his failure. Jerome is very tempted to shoot Flem but instead he kills a deer, proving the problem is Flem’s aim. When they go home, Jerome hides the rifle in his room.
During lunch, Jerome says he got a call from Robbie, who is looking for Flem. This gets on Flem’s nerves and he snaps, saying Jerome is lying. Mary scolds him for his attitude and Jerome insists he’s telling the truth, so Flem bursts out of the room.
The next day, Flem gets a letter written by Jerome pretending to be Robbie. The message asks Flem to meet Robbie at the cliffs because he’s in trouble. Before leaving, Flem looks for the rifle and Jerome says he took it to the shop to be repaired since Flem said it wasn’t working well.
Flem has to play along not to get caught and apologizes for his outburst at the table. After grabbing a knife, Flem goes to the cliffs with Sim and calls out for Robbie. Suddenly he falls down into a hidden pit and breaks his legs.
Flem screams in pain and begs Sim for help, but the machine doesn’t understand. At that moment Jerome shows up and only stares at Flem with a rock in is hand, making Flem realize the boy knows the truth. A desperate Flem begs for mercy yet Jerome ignores him and continues to stare, letting him suffer under the burning sun.
Eventually Flem starts screaming for help again and begs Jerome to think of his sister and the baby. He goes on a long speech about accidents and regret, making Jerome so angry that he finally shoots Flem, killing him. When Jerome returns home, he lets Mary think that Flem abandoned her and doesn’t tell her how Ernest really died.
Thanks to the money from the crops, they can afford real food now and the siblings agree they can finally buy the machine so Katherine can come live with them. Jerome erases all the footage from Sim, ready to start over.
