A sick, human-eating reptile knocks on the front door of a human man's shack in no-man's-land. The man surmises that the creature looks more scared than he is and lets it in. The creature is huge and takes up all the space in the shack. The man removes a plastic tag with a faded number from one of its ears and serves it broth. The creature thanks him in English, with the voice of what sounds like a snake. After it falls asleep, the man finds a book of poetry and dried flowers in the creature's pouch. He concludes, based on its anatomy, that the creature is a girl and a child, around seven years old. The man also realizes that such creatures are specifically engineered to kill humans. As one of the sole survivors of what was presumably an apocalypse that wiped out his family, the man has been living in this shack in no-man's-land, in hiding, for a decade. When the creature wakes, the man introduces himself as Ben. They step outside and see, on the slope below them, a group of reptilian creatures killing another one of their kind. The creature, whom Ben names Rosie because she reminds him of his late pet dog, urges him back into the shack. That night, one of the creatures approaches Ben's shack, though Rosie manages to fend it off. Understanding that they are no longer safe in the shack, Ben and Rosie make their way to higher ground. However, when a helicopter sounds off above them, Ben realizes that Rosie must have an id chip embedded in her neck. He removes it and they venture on, leaving the helicopter behind. Ben knows that Rosie is sick but isn't sure how to help her. He offers himself up as sustenance. However, she adamantly refuses, explaining that she is "temporary," so it wouldn't make a difference if she died now. There is a timer in her heart, and she isn't sure when it will go off. In a hanging valley sheltered by boulders and trees, Ben and Rosie build a new cabin.