A passenger of a hijacked airliner who happens to be an airplane engineer works to deactivate a chemical weapons bomb after the hijackers kill the pilot and threaten to kill all the passengers on the plane.

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.