Parts: 4
Writer: Robert Holmes
Airdates: 2 January 1971 - 23 January 1971
Production Code: EEE
Megalomaniac of the Week: the Master
Creature Feature: Nestene and Autons
Special Guests: UNIT (the Brigadier, Benton, Yates), the Time Lords
Story: Amidst a group of circus tents and trailers, a strange noise startles the circus owner, Rossini - just as a horsebox materializes out of thin air. From it emerges a well-dressed gentleman; when Rossini confronts him, he claims to be known as the Master ("universally"). Condescending and dangerous, the Master quickly subdues Rossini and then has him knocking out security guards while the Master carries out a bit of theft.
When the Doctor learns that the Nestene sphere left over from their attempted invasion of Earth has been stolen from a museum, he is immediately worried. Nearly as worrisome is his new assistant Jo, who rather fails to live up to his expectations by being slightly less scientific and slightly more clumsy than he had wished. Meanwhile, the Master proceeds to take control of a radio telescope and plug the Nestene sphere into it. With that accomplished, the second Nestene invasion has begun...
Using his considerable hypnotic powers, the Master takes control of a plastics factory and begins to manufacture Autons, as well as a variety of other special Nestene treats, each one as deadly as the last. Unless the Doctor, Jo and UNIT can locate the factory and stop him from carrying out his plans, this time the Nestene Consciousness will be successful in taking over the Earth...