One of Earthworm Jim's enemies from the animated television series, Evil Jim, has returned to cause chaos in the Galaxy. Our hero's evil doppelganger has stolen a doomsday device, the Inter-Dimensional Transporter-of-Doom, which he plans to sell to the highest bidder. Earthworm Jim has to search numerous worlds for the doomsday device and recover it from his evil twin, on a new quest that will bring him face-to-face with many of his oldest foes.