Plot
In 1963, the town of Gatlin, Nebraska, suffers a severe drought. In a tent, a boy preacher claims that a god, whom he calls "He Who Walks Behind the Rows", has spoken to him in his dreams. He tells the other children that the adults in the town are the cause of their recent problems as he considers them blasphemous, the children then decide to establish a death cult of children and teenagers to get rid of everyone over the age of 20.
Twelve years later, Burt, a Vietnam veteran, and his temperamental wife Vicky, travel through rural Nebraska to save their crumbling marriage with a second honeymoon. As they argue, a young boy named Joseph stumbles out of the cornfields, runs to the road and gets accidentally run over by Burt. The couple stops and examine Joseph's corpse and find out that his throat was slashed before being run over, Burt puts Joseph's body inside the car's trunk, heads to the cornfields and finds Joseph's briefcase, Burt returns back to his car, informs Vicky about the briefcase, they then decide to go to Gatlin to report the incident, not knowing that they are being watched by Isaac Chroner, a nine-year-old boy and the current leader of the cult and his second-in-command, the 18-year-old Malachai Boardman.
As the couple drive to Gatlin, Vicky opens the briefcase and finds a creepy handmade thing made out of corn husks, which Vicky recognizes as a pagan creation. Meanwhile, Isaac informs the cult about the couple's presence and they are similar to "the blue man", a police officer who was one of the sacrifices. After stopping in an abandoned gas station, Burt and Vicky finally make it to Gatlin, they find the entire town deserted and abandoned with nobody around, Burt decides to investigate the town's church, despite Vicky's insistence of leaving the town. Burt finds the church empty, with its crucifix identical to the one that was in Joseph's suitcase, while Vicky is being stalked by the cult. She soon meets the cult members and retreats back into the car, but can't leave since Burt took the keys with him, the cult members begin to demolish the car, with Burt ignoring Vicky playing the horn. As Malachai approaches Vicky, the latter threatens the former with Burt's rifle, but Malachai moves out of the way, killing one of the cult members instead. Vicky is then fatally stabbed by Malachai. Burt, having been alerted by the gunshot noise of his rifle, exits the church and finds the cult surrounding the car, and Malachai soon sets the car on fire and it explodes with Vicky's body inside.
When Malachai tells Burt that the sacrifice time is coming, Burt runs into a alleyway, and gets cornered, with Isaac throwing a knife at Burt's arm from a rooftop, Burt retaliates by breaking the knife in two. After killing two of the older members, Burt runs to the cornfields with the cult members stopping right as he enters the cornfields. Meanwhile, back at the alleyway, Isaac tells Malachai that the latter's faith with He Who Walks Behind The Rows has been questioned due to Malachai spilling Joseph's blood on the corn, so Malachai prays to appease Him. The leaders later meet with the cult at the cornfields, a member sees Burt in there, and the cult, under Malachai's order, chase Burt down.
During the chase, Nahum, one of the younger cult members, tells Malachai about having a vision of He Who Walks Behind the Rows, leading Malachai to believe that Nahum will be the next prophet after Isaac. As he escapes the cult, Burt soon has hallucinations of the Vietnamese war, and kills more cult members, including Nahum. Night soon falls, and the cult abandon the search and head to the church, where two teenage members, a girl and a boy, walk to the stand, disrobe and have sex in front of Isaac and the entire congregation. Meanwhile, Burt, now lost in the cornfields, wanders aimlessly, searching for the road and having a nightmare of those he killed, intentionally and accidentally. Soon, the plant life of the cornfields begins to attack Burt, stumbling him into the clearing. To Burt's shock, he finds Vicky's corpse on the clearing and hears rustling around him, Burt soon hallucinates that Vicky's corpse talking to him about that being sacrificed "is not so bad". The sky soon darkens; He Who Walks Behind The Rows arrives and Burt screams before his oncoming death.
The next day, Isaac informs the cult that He Who Walks Behind The Rows is angry with them for being unable to kill Burt and having to kill him by Himself, Isaac lowers the age limit from 19 to 18 (as the blue man was also killed by He Who Walks Behind The Rows years ago and lowered the age limit from 20 to 19) as punishment for their failure, Malachai obeys this command and leaves with the rest of the cult. When Isaac is about to leave, he yells "Scarecrow!", and this scarecrow is revealed to be Burt's corpse, Isaac soon leaves after burning a tarp with the dead cult members.
In a post-credits scene, the cult returns to the cornfields at night. Malachai talks to his pregnant girlfriend Ruth about entering the cornfields. Ruth has her doubts and has a vision of herself setting the cornfields on fire, she tearfully says goodbye to Malachai as he and the other 18-year-old cult members walk into the cornfields and perish to He Who Walks Behind The Rows. As they disappear into the corn, Isaac silently glares at Ruth, a hint that he knows her thoughts of burning the corn.
