The Doctor and the crew of the Wheel battle against the invading Cybermen.
The Cybermen reveal their plans to invade Earth, using the Wheel as a guiding beacon.
The station is in danger of being destroyed by the approaching meteor storm.
Cybermats eat the Wheel’s bernalium supply, forcing the crew to board the Silver Carrier.
The Doctor and Jamie are rescued and taken aboard the Wheel but Jamie sabotages the laser.
The Doctor and Jamie are forced to abandon the TARDIS when the mercury fluid link breaks.