Second Doctor, 1968, story 54, The Wheel in Space.
EPISODE 1
The explosion of the mercury fluid links forces the Second Doctor and Jamie McCrimmon to evacuate the TARDIS to avoid mercury fumes. Until it can be replaced, the craft is marooned. They are on a space vessel, deserted apart from a servo robot. The robot detects the intruders and in response redirects the rocket from aimless wandering, sending it on a course, and the shock of change causes the Doctor to hit his head, briefly concussing him. The robot also releases a group of egg-shaped white pods into space, and the mysterious things direct themselves toward a nearby spaceship shaped like a giant wheel, attaching themselves to its exterior by a seeming act of will. When the robot becomes aggressive, Jamie destroys it, but the Doctor's condition worsens and he collapses. Jamie then looks into space on the observation port.
The Wheel is an Earth space station observing phenomena in deep space and is staffed by a small international crew. They are concerned by the sudden drops in pressure which, unbeknownst to them, coincide with the pods attaching themselves to the exterior of the Wheel. Controller Jarvis Bennett is also worried that the Silver Carrier, a missing supply vessel eighty million miles off course, has suddenly turned up nearby and is not responding to radio contact. He decides to destroy it with the Wheel's powerful x-ray laser.
EPISODE 2
The destruction of the Silver Carrier is only prevented when the crew hear a deafening burst of noise from the vessel. Jamie has managed to alert them to his presence aboard the Carrier and in a short time he and the unconscious Doctor are rescued and taken aboard the Wheel. The resident medic, Doctor Gemma Corwyn, sees to the Doctor, and Jamie is given a guided tour by the sparky young para-psychology librarian, Zoe Heriot. Bennett remains suspicious of the new arrivals, fearing they could be saboteurs opposed to the space program. He decides to use the x-ray laser on the Carrier now that the two refugees have been rescued, little realising the TARDIS is still on board.
On board the Carrier, meanwhile, two large pods have split open to reveal two Cybermen inside.
EPISODE 3
Jamie intervenes to sabotage the laser, which only further infuriates Bennett. There is a potential meteor shower heading for the Wheel - and they now have no way to repel it. When the Doctor recovers in the sickbay he does not approve of this action. He remains groggy and unclear, but convinced a major danger lurks on theSilver Carrier. He calculates that the ship did not drift to their sector but was deliberately piloted there. The Wheel's crew, however, are more concerned with the impending meteor shower.
The small pods sent to the Wheel contained Cybermats. These have been set to work in consuming bernalium rods in the Wheel's stores. The bernalium is essential to power the X-ray laser. The Cybermen have deliberately made the star in Messier 13 go nova, forcing the Wheel crew to look for their bernalium and find it missing. When this happens, the Cybermen are sure the crewmen will come to the Silver Carrier for the bernalium, which can then be transported into the Wheel - with a surprise inside.
An engineer called Bill Duggan has noted the depleted stocks and the presence of the Cybermats. His slowness in reacting allows another crewman, Kemel Rudkin, to fall victim to the Cybermats. Jarvis Bennett overreacts in panic to this state of affairs, stripping Duggan of his position and imposing tighter controls. The Doctor's solution is more practical - he uses the X-ray machine to scan inside a pod that has been found but cannot be opened. The Cybermat within is easy for him to identify, but Bennett does not accept the danger. Medic Gemma Corwyn, who has formed an alliance with the Doctor, fears for Bennett's mental state. He seems unable to deal with escalating events. His behaviour seems to grow more and more bizarre and detached from reality.
He has sent two crewmen to the Silver Carrier, Laleham and Vallance. They are taken over by the Cybermen and used to prepare the bernalium crates for the Wheel with the two Cybermen hidden inside.
EPISODE 4 s
This ruse works and the crates are soon aboard the Wheel, with Duggan and his colleague Leo Ryan glad to have access to a new power supply for the x-ray laser, which they are slowly managing to repair. As the Doctor tries to persuade the space station of the danger of the Cybermen, an engineer called Chang is killed by the emerging Cybermen when he is sent to fetch the new bernalium supply. They dispose of his body in the waste incinerator. Laleham and Vallance arrive at the laser with the supply of bernalium for Duggan, who soon falls victim to the same mind control and becomes the third agent of the Cybermen on the Wheel. He is sent to destroy the communications unit and does so before being gunned down. A Cyberman soon corners the Doctor and Jamie.
EPISODE 5
The Doctor and Jamie escape and have deduced that the fortuitous supply of bernalium has a deeper significance. He has also worked out the late Duggan was under mind control and instructs Dr Corwyn to use a basic transistor system attached to each of the crewmen to block this technique. A further step forward is taken when the crew use a sonic wave to disable and kill the Cybermats on the Wheel, but it is clear the Cybermen are at large and going on with their plans. Laleham's death is no obstacle as another engineer, Flannigan, replaces him. The Cybermen have invested time in repairing the x-ray laser, evidently needing it ready for use. When the meteorites are finally due to hit they can be deflected and obliterated. The Cybermen need the Wheel intact to use as a launching point for an invasion of Earth, desperate for the planet's mineral wealth. The Wheel's radio beam will enable them to do this. The Doctor has decided he needs the time vector generator which he removed from the TARDIS. Jamie and Zoe are chosen for a space-walk to the Silver Carrier. As they slowly make their way from the Wheel to the ship, the meteorites approaching the Wheel get dangerously close to them.
EPISODE 6
The crew have fully repaired the x-ray laser and use it to destroy the meteorites. They are picked off one by one by the Cybermen or their agents. Gemma Corwyn dies trying to stop the Cybermen from damaging the Wheel's oxygen supply. Shocked back to clarity by her death, the mad Jarvis Bennett is mowed down when he seeks revenge. Leo Ryan takes control as the Doctor warns there is a huge Cyberman spacecraft coming to the Wheel.
Jamie and Zoe return with the Doctor's time vector generator. Flannigan tries to overpower them when they get back to the Wheel, but he in turn is overwhelmed by Leo and Enrico Casali, the communications officer, and his conditioning is broken. The Doctor also manages a triumph, electrocuting one of the Cybermen and confirming to himself the full nature of their plans. He uses the time vector generator to boost the power of the x-ray laser and this destroys the advancing Cybership. A troop of Cybermen space-walking to the Wheel are also dispensed with, while Jamie and Flannigan free Vallance and destroy the remaining Cyberman inside the Wheel.
With the invasion repelled, the Doctor and Jamie return to the Silver Carrier with the mercury they need for the TARDIS. They are accompanied by Zoe, who quietly stows away in a box as the time vessel departs. As she seems determined to stay, the Doctor decides to warn her of the dangers they encounter. He uses a mental device to project images from his mind to tell her of his and Jamie's last encounter with the Daleks...
