Ep 4. Spearhead from Space: Part 4

Exiled to Earth in the 20th century, the Doctor has been collaborating with the Brigadier and his UNIT team to investigate a mysterious invasion by the Autons, plastic dummies that come to life and wreak havoc in the streets. In "Spearhead from Space: Part 4," the Doctor continues to race against time to uncover the source of the Auton invasion and put a stop to their plans before it's too late.

With the help of his new companion Liz Shaw, a brilliant scientist recruited by UNIT, the Doctor learns that the Autons have been unleashed by a powerful alien intelligence known as the Nestene Consciousness. The Nestene, a formless entity that exists in a sort of hivemind collective, seeks to colonize Earth and turn it into a new home for its plastic servants. To accomplish this, it has allied itself with a human collaborator named Channing, who is working to install a transmitter that will allow the Nestene to exert control over all the plastic on the planet.

As the Doctor and Liz work to disrupt Channing's plans, they discover that the Nestene's ultimate goal is even more sinister than they had imagined. The consciousness plans to use the Autons as a sort of vanguard army, softening up the planet for a full-scale invasion by its own kind. With the fate of the Earth hanging in the balance, the Doctor must use all his wits and resourcefulness to outmaneuver the Nestene and its minions, and stop Channing's plot before it's too late.

Along the way, the Doctor and Liz face a variety of challenges and setbacks, from being trapped in the basement of a department store infested with Autons, to having to use their own scientific knowledge to figure out how to neutralize the Nestene's psychic energy field. They are aided in their efforts by the UNIT team, including Brigadier Lethbridge-Stewart, Sergeant Benton, and Dr. Henderson, who provide backup and logistical support throughout the operation.

As the stakes get higher and the danger more intense, "Spearhead from Space: Part 4" races towards a thrilling and unpredictable climax. With the fate of the world hanging in the balance, the Doctor, Liz, and their allies must face the full might of the Nestene Consciousness and its vast army of plastic warriors. Will they be able to save the Earth from destruction, or will the Autons be the first wave in a new era of alien domination? Tune in to find out.