The Tardis materialises on a massive Urbankan starship filled with ancient ethnic groups.

The time ring takes the Doctor, Sarah and Harry back to Nerva, but to a period many thousands of years earlier than their previous visit. The station is currently acting as a beacon warning space traffic of the existence of a new asteroid orbiting Jupiter.

Barbara is mistaken for an Aztec priest.

Barbara is given an honored position.

Stemming from The Green Death series, the Doctor realizes the consequences from keeping the blue crystal found on Meteblis 3. Meanwhile, Sarah is asked to investigate a suspicious transcendental meditation group.

A group of spider-triplets are commanded to retrienve a blue crystal which was taken by the Doctor. However, various other parties have an interest in the crystal as well, putting the Doctor and friends in a precarious position.

A mysterious woman who can't even remember her own name, falls from the sky.

The Doctor hopes to rescue his partner Sarah on Metebelis 3 and is given the ultimatum of returning the blue crystal to empress Great One or see all of mankind destroyed. Weighing his options, the Doctor considers his own life.

The Doctor returns the blue crystal to the spider empress, Great One, and realizes the power she gets from having it may not be a good thing. He must now face his inner demons and greatest fears if there is going to be resolution.

While an exhausted Doctor falls asleep, a robot steals blueprints for a disintegrator gun.

The Doctor helps the Brigadier investigate the culprit behind a series of crimes.

The Tenth Doctor's nemesis has been reborn; a shadow falls across the entire universe.

Creatures attack The Doctor and Clara while they are trapped on an Arctic base, and they receive help from a surprising source.

The Doctor, a journalist and a superhero team up to save New York City.

The Doctor, refusing to face regeneration, teams up with his former self, a British army captain, and Bill Potts for an adventure.

The Doctor and Sarah realize that Hilda Winters, a director for Think Tank, programmed the robot that stole a disintegrator gun. The organization planned to start a nuclear war, eventually win and rule the world.

While Think Tank hides in a bunker waiting for the nuclear holocaust to begin, the Doctor is in a frantic effort to stop the organization from achieving their goal of world domination.