To escape from the volcanic eruption on Dulkis, the Second Doctor uses an emergency unit. It moves the TARDIS out of normal time and space. The travellers find themselves in an endless void where they are menaced by white robots. Having regained the safety of the TARDIS, they believe they have escaped — until the ship explodes. They find themselves in a land of fiction, where they are hunted by life-size clockwork soldiers and encounter characters like Rapunzel, the Karkus, and Swift's Lemuel Gulliver.

Army radiation experiments awaken a subterranean monster from a fissure that feeds on energy and proceeds to terrorise a remote Scottish village. An American research scientist at a nearby nuclear plant joins with a British investigator to discover why the victims were radioactively burned and why, shortly thereafter, a series of radiation-related incidents are occurring in an ever-growing straight line away from the fissure.

A mysterious spacecraft captures Russian and American space capsules and brings the two superpowers to the brink of war. James Bond investigates the case in Japan and comes face to face with his archenemy Blofeld.

The time travellers arrive in Scotland just after the Battle of Culloden. The Second Doctor gains the trust of a small band of fleeing Jacobites by offering to tend to their wounded Laird, Colin McLaren. While Polly and the Laird's daughter, Kirsty, are away fetching water, he and the others are all captured by Redcoat troops commanded by Lieutenant Algernon Ffinch.

维基：

维基：

The TARDIS arrives on the planet Telos where an Earth archaeological expedition, led by Professor Parry, is attempting to uncover the lost tombs of the Cybermen. With a lot of help from the Doctor the archaeologists enter the tombs. There, one of the party, Klieg, reveals himself and his business partner, Kaftan, to be planning to revive the Cybermen.
He wants to use their strength, allied with the intelligence of his own Brotherhood of Logicians, to create an invincible force for conquest. It transpires however that the tomb is actually a giant trap designed to lure humans suitable for conversion into further Cybermen - a fate that almost befalls Kaftan's assistant Toberman.
After fending off an attack by Cybermats - small but dangerous cybernetic creatures - the Doctor eventually defeats the revived Cybermen, led by their Controller, and reseals the tombs. The Controller is apparently destroyed in the process.

This season featured the first ever UNIT story, The Invasion, which showcased the return of Brigadier Lethbridge-Stewart. It also featured the first official appearance of Time Lords and the as yet unnamed Doctor's home planet (another member of Susan and the Doctor's race, the Monk, had appeared previously, but without much elaboration and without using the term "Time Lord"). It also marked the tenure of Patrick Troughton as the Second Doctor. It consisted of seven serials and forty-four episodes, including two epic-length storylines: the eight episodes of The Invasion and the ten-episode The War Games.

The TARDIS arrives on the planet Telos where an Earth archaeological expedition, led by Professor Parry, is attempting to uncover the lost tombs of the Cybermen. With a lot of help from the Doctor the archaeologists enter the tombs. There, one of the party, Klieg, reveals himself and his business partner, Kaftan, to be planning to revive the Cybermen.
He wants to use their strength, allied with the intelligence of his own Brotherhood of Logicians, to create an invincible force for conquest. It transpires however that the tomb is actually a giant trap designed to lure humans suitable for conversion into further Cybermen - a fate that almost befalls Kaftan's assistant Toberman.
After fending off an attack by Cybermats - small but dangerous cybernetic creatures - the Doctor eventually defeats the revived Cybermen, led by their Controller, and reseals the tombs. The Controller is apparently destroyed in the process.

维基：

The TARDIS materialises in England in the 1970s and the time travellers meet a girl named Isobel whose uncle, computer scientist Professor Watkins, has recently gone missing. The Doctor offers to help track him down, starting at the place where he last worked - the London HQ of International Electromatics, the world's major supplier of electronic equipment.
His initial suspicions about IE's managing director, Tobias Vaughn, are confirmed after he becomes reacquainted with Lethbridge-Stewart, now promoted to Brigadier and in charge of the British branch of the United Nations Intelligence Taskforce (UNIT), and learns that there have been other disappearances at IE premises.
He discovers that Vaughn is in league with the Cybermen in a plan to invade Earth, but is also plotting against them with the aim of seizing power for himself. Watkins is being forced by Vaughn to develop the cerebration mentor, a machine designed to generate emotional impulses as a weapon against the Cybermen.
The Cybermen immobilise most of Earth's population - sending a hypnotic signal through special circuits incorporated in all IE equipment - and launch their invasion. The Doctor has managed to protect himself and his friends from the signal and - with help from an embittered Vaughn, who is killed during the fighting - the invasion is eventually defeated.

A recently-deposed "Estrovian" monarch seeks shelter in New York City, where he becomes an accidental television celebrity. Later, he's wrongly accused of being a Communist and gets caught up in subsequent HUAC hearings.