Violence comes to the isolated town of Fortitude in the Arctic Circle, one of the safest towns on Earth. As mysterious phenomena plague the town in the aftermath of a murder, the inhabitants realize that no one can be trusted... and all is not that it seems.

As a ferry carrying 300 passengers from Denmark pulls into an Icelandic town’s small port, heavy snow begins to fall. The ferry can’t leave until the storm passes and the main road into town is impassable. A mutilated and dismembered body washes on the shore, an unidentifiable man murdered only hours ago. The local police chief, Andri Olafssun, whose personal life is in shatters, realizes a killer has descended into his town. As word spreads, order disintegrates into chaos as the ferry’s passengers and the town’s residents realize they are all possible suspects and that a killer is trapped among them.