Forbidden to continue his travels through time and space by his fellow Time Lords, the newly regenerated Doctor begins his exile on Earth and finds himself hurled into one of his most exciting and terrifying adventures.
But the Doctor is not the only alien intelligence arriving on the planet. A shower of mysterious meteorites signals the coming of the Nestene Consciousness - an evil, cosmic, collective being with just one goal - total conquest of Earth. The Nestenes possess a special ability to control plastic and are making hordes of Autons - indestructible, armed, plastic mannikins, only awaiting the Nestene command to start their killer rampage.
Brigadier Lethbridge-Stewart, scientist Liz Shaw and U.N.I.T. enlist the Doctor's help to defeat the relentless Auton invasion, but the Doctor has problems of his own.