SPRECO (the SPace REfuse COllector) returns to Homebase Five from escaping the castle after the lightning accident that sent him there. But the complex was deserted totally devoid of all life. From a nearby Construct-bot, SPRECO finds out that the humans had been enslaved and the complex taken over by an evil being calling himself "The Mindmaster". In order for SPRECO to destroy him he has to find the experimental DeActi-Unit, which the Mindmaster has split up into 4 sections and hidden throughout the complex. SPRECO would have to find these parts, take them to the Mindmaster's hiding place, piece it together and re-activate the unit in order to free the people from the Mindmaster's control.