Twenty years have passed since the doomed Bugs 2 mission, and a strange new disease is ravaging Earth. To save his friend from the malady, Akari Hizamaru enters an underground tournament only to find himself pitted against a savage foe.

In the darkness of space, Annex 1 becomes a bloody backdrop for the terraformars' rampage. Akari and Michelle manage to push back before making a mad dash for the mutational serum, now almost completely destroyed.