Note: Subsequently remastered and re-released as part of The Lost TV Episodes: Collection Five box set.
'The Cybermen need to colonise. They must have the treasures of the Earth!'
Taking drastic measures to escape a TARDIS malfunction, the Doctor and Jamie arrive on a rocket, apparently deserted in space, and soon encounter its aggressive robot guard. When a blow to the head then renders the Doctor unconscious, Jamie's only hope of rescue lies in contacting the Wheel space station which is orbiting nearby.
In fact the rocket has other occupants, who are sending out mysterious egg-like spheres to penetrate the Wheel's outer surface. What dangerous cargo do the spheres bring to the human crew of the Wheel, and what is the intention of those who are sending them?
It's not long before the Doctor and Jamie realise that their old adversaries, the Cybermen, are seeking to invade first the Wheel and then Earth itself. One by one the space station's crew are being taken over, whilst deadly rodent-like Cybermats roam the space station and steadily consume its fuel supply. On top of everything, a meteorite storm is approaching — but the Wheel's defence system has been disabled...
This six-part adventure, first broadcast on BBC1 in 1968, features the debut of the Doctor's companion Zoe, played by the soundtrack's narrator Wendy Padbury.