Whilst he is exploring an asteroid Koenig is taken over by an alien race known as the Kalthon, who replace him with an exact double. In consequence every action ordered by the fake Koenig is solely for the benefit of the Kalthon and to the detriment of the welfare of the Alphans. Helena realizes that something is wrong when 'Koenig' is cold to the touch and needs to convince the other crew members.

The Alphans land on a planet seemingly devoid of any human existence but being run by a group of machines. The machines explain to the visitors that their human overlords are in a state of regeneration but the chief machine, the Guardian,sees the Alphans as posing a threat and it is down to two newly regenerated females known as A and B to decide their fates.