When Virginia and her husband Jack spend a long weekend in the idyllic countryside, they encounter a creature that tears their lives apart. While the attack has an effect on each of them, it brings out the worst in Jack.

In 709 AD, in the Iron Age, a spacecraft crashes in the Viking kingdom of Herot, Norway, and the pilot Kainan survives. He turns the beacon on; learns the language and culture of the planet using a machine; and finds that the predator, Moorwen, that he was transporting, had escaped. While chasing the alien monster, he finds a village completely destroyed and is arrested by the warrior Wulfric, believing that he killed the locals - Kainan is brought to Herot as a prisoner.