Although their father initially dismisses their claims, siblings Hector, Jack, and Lozzy have reported seeing a horrifying man-pig hybrid around their family’s New Zealand bungalow for months. The children suspect the creature, the “pig thing,” was the cause of their dog and chickens’ disappearances. The family originally lived in England, but chose to move to New Zealand’s countryside for a fresh start. When he hears their story, the children’s father, Bill, assumes they are making it up because they still haven’t acclimated to the new country. However, as the family is watching television one night, they all see the pig thing stand against the porch window. With the only two police officers at the nearest station called away to handle some other business, Bill calls the closest neighbors, the Pitchfords. When the elderly couple does not answer, Bill and his wife, Jan, worry the pig thing must have killed them first. As a last resort, Bill takes a flashlight and prepares to head down the driveway to start their car and drive his family away from the monster. Jan begs to go with him, but he tells her to stay with the children. She locks herself with them in the laundry room after he leaves, but when he does not return, she goes after him, telling the children to stay in the laundry. Jan does not return either.

Realizing both his parents seemed to vanish without any auditory signs of struggle, Jack, the middle child, fears the pig thing could be so strong that no person could stand a chance. As their mother’s period of absence stretches and stretches, Lozzy, the youngest child, sobs and whimpers, only temporarily comforted by her brothers’ reassurances. After Jack opens the laundry’s freezer to give Lozzy ice cream, he asks Hector what he thinks of this situation. Hector, the oldest child, frightened but resolved to be brave, tells Jack he will leave the house and fetch the Pitchfords. Jack objects, thinking of the darkness and the monster it holds, but Hector tells him he knows the way. Though Jack still pleads for him not to go, Hector leaves. To further prevent the pig thing from accessing them, Jack clears out the freezer and crawls inside it with Lozzy. He brings the family dog’s blanket with them for a cushion and slightly props open the lid of the freezer for air. Lozzy complains about the blanket’s scent, and Jack hopes the cold conditions of the freezer will prevent the pig thing from smelling the children if it enters the house. Hector reaches the neighboring house, and Mrs. Pitchford takes him to her husband's workshop. When Mr. Pitchford comes in, he has on his sheep-shearing gloves and apron and comments on Hector’s evasiveness and agility. At Hector’s desperation for his siblings, the Pitchfords drive to the bungalow to look for them. Mrs. Pitchford then enters the house, looking for the younger two siblings. On her search around the bungalow, Mrs. Pitchford opines to herself of the inferior quality and irritating nature of the homes of the new inhabitants of the New Zealand countryside. The Pitchfords are longtime residents of the area, and each new home erected for each new settler scars the land that was once solely theirs (apart from the native Maori). She checks the laundry room, noting the freezer has oddly been emptied and is lined with an old blanket. She then checks the children’s rooms, finding runny, bloody stools on the carpet. The pig thing, or “my girl” in the Pitchfords’ eyes, has eaten the two remaining children before excreting them and fleeing the house. Mrs. Pitchford lovingly cleans up the remains of Jack and Lozzy, slipping them into a pillowcase and some Tupperware. She then takes them outside and comes back to the room to scrub out the stains. Once finished, she places the remains in the car and asks Mr. Pitchford if they should search the nearby creek for their daughter. He smiles and says no, telling his wife their girl has her own family now, and that they have done all they could for her. He says they taught their daughter how to pace herself, and that if she likes eating the new residents, he and his wife have no need to care because they came to this place first anyway.