Tom's goldfish is horrifically transformed after his evil scientist big brother's experiment goes wrong, an accident that imbues the goldfish with hypnotic powers and a thirst for revenge.

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.