Magnus and his friends set sail for the farthest borders of Jotunheim and Niflheim in pursuit of Asgard's greatest threat, Loki's demonic ship full of zombies. While Loki prepares his ship, Naglfar, to begin the final battle of Ragnarok, Magnus and his friends set sail to reach the vessel before it's ready, but angry sea gods and a fire-breathing dragon may prevent them from arriving in time.