The Mysterons use a Russian Druzynik tank to blow up the town of Ragnarok and reconstruct it and it's residence as Mysteron replicants. Captain Scarlet & Captain Blue are sent to track the Druzynik and enter the town where they end up stumbling onto a Mysteron plan to dig up a meteorite that has been under the town for millions of years. The meteorite contains alien spores that the Mysterons plan to use to wipeout humanity.