The TARDIS lands on the Moon in 2070 but Jamie injures himself during a spacewalk. Seeking help, the travellers are treated with suspicion at the weather control base where a plague has struck crew.
Polly discovers that the Cyberman are abducting the plague victims, but nobody believes her until it is too late.
The Cybermen have taken control of the moonbase and are preparing to use the weather control systems to wreak havoc on Earth.
The moonbase is cut off from Earth and under siege. The Cybermen launch an all-out attack and the Doctor formulates a dangerous plan to repel the invaders.
