The commanding controller of Lunarville 7, a small colonised base on the opposite side of where the main Mysteron complex is located on Mars, announces that he has made direct contact with the force, and agreed to a undisturbed, and peaceful settlement, and to finally end the war of nerves, but this is a trick by the Mysterons, as the controller and his personnel aid are reconstructed agents, and have Captain Scarlet, Captain Blue and Lieutenant Green trapped on the compound when they are sent to investigate how he managed to make a deal with the Mysterons.

When suspecting that the controller and his right-hand man could be Mysteron agents, they non-attentively leave Lunarville 7, and travel to the Humboldt Sea, the far side of the Moon, where an enormous, and potentially powerful Mysteron complex is being developed and built in Crater Number 101.