For centuries, no one had visited the three planets of the Tehric system. Tundra, the Aztec Planet and the Red planet had been abandoned when technology advanced to a stage where highly dangerous automated military units developed self-awareness - a devastating effect for all living things in the Tehric system. Originally intended to protect vital power cores from invaders, the machines rebelled, deciding to wipe out all biological life. With no other options, humanity withdrew, leaving the system to the mercy of this new breed of killers. Having since evolved to replace biological life, there is little evidence of the human race - only the ruins of their cities remain.