The Cybermen return to menace the second Doctor Patrick Troughton, in this six-part story from 1968 - only two episodes of which survive in the BBC Television Archives. When the TARDIS materialises on the seemingly deserted Silver Carrier rocket, the Doctor is rendered unconscious by a Servo Robot. It's up to Jamie to contact the nearby Wheel space station for; however, the Wheel is soon under attack from the emotionless Cybermen. The Doctor's old enemies intend to use the Wheel as a beacon for a full-scale invasion of Earth. In their bid to halt the approaching Cyber-fleet, the recovered Doctor and Jamie are helped by the crew of the Wheel - which includes a plucky young astrophysicist named Zoe Herriot. But with the space station already infiltrated by Cybermats, and many of the humans under hypnotic Cyber control, the odds are stacked against them...This exciting adventure introduces Wendy Padbury to the series as new companion Zoe.