3. The Cybermen, The Wheel In Space
The Cybermen take control of the Silver Carrier, a supply vessel, and set it drifting off course with only a servo robot, a source of Bernalium, Cybermen and Cybermats, and some white pods for hiding purposes on board. When the Doctor and Jamie board the vessel, the robot detects them and pilots the Silver Carrier towards a scientific, non-military space station, and also sends some white pods containing Cybermats towards it. The Cybermats will destroy the space station's Bernalium, which powers their defensive laser, while the Cybermen send a star nova so that the crew of the space station will need to fire the laser, then realise they are out of Bernalium, and so will absolutely have to try boarding the Silver Carrier in case there is some on board. The Cybermen hidden on board the Silver Carrier will then take over the minds of whoever is sent to investigate so that they can take the Cybermen to the space station, hidden in the Bernalium crates. They then repair the laser so that the meteors from the exploding star dont hit the station, as they need to use it as a homing beacon for the Cyberfleet. From here they can invade the Earth, which they want to do this time because of its mineral wealth. Logic, it transpires, really does not look like you'd expect it to.