The search for the Key to Time lands Dr. Who and Romana on a moon inhabited by swamp people---and a gigantic monster. Dr. Who: Tom Baker. Fenner: Philip Madoc. Romana: Mary Tamm. Thawn: Neil McCarthy. Dugeen: John Leeson. Rohm-Dutt: Glyn Owen.

The final segment of the Key is traced to the planet Atrios, engaged in a long war with the neighbouring Zeos. The Marshal of Atrios intends a final strike to destroy the Zeons, but the Doctor and Romana discover that Zeos is deserted and the war is being co-ordinated by a computer called Mentalis, built by one of the Doctor's old Time Lord Academy friends, Drax.

Two alien seed pods are found buried in the Antarctic permafrost and the Doctor realises that they are from a Krynoid, a form of plant life that infects and transforms all animal life on planets upon which it becomes established.

With a new assistant, Romana, the Doctor begins the search for the Key to Time. Guardian: Cyril Luckham. Voice of K9: John Leeson.

The final segment of the Key is traced to the planet Atrios, engaged in a long war with the neighbouring Zeos. The Marshal of Atrios intends a final strike to destroy the Zeons, but the Doctor and Romana discover that Zeos is deserted and the war is being co-ordinated by a computer called Mentalis, built by one of the Doctor's old Time Lord Academy friends, Drax.

The White Guardian gives the Doctor a quest to find the six disguised segments of the Key to Time which, when assembled, will be used to restore the balance of the cosmos. To aid him he is given a new companion, a female Time Lord called Romana, and a tracer device.

The Doctor is called in to investigate a pair of mysterious seed pods in the Antarctic. As the Doctor looks to uncover their mysteries, a ruthless collector arrives to add the seeds to his menagerie. Things take a turn when it is discovered that the pods harbor intelligent life with sinister plans of its own.

Two alien seed pods are found buried in the Antarctic permafrost and the Doctor realises that they are from a Krynoid, a form of plant life that infects and transforms all animal life on planets upon which it becomes established.

On a holiday in Paris, the Doctor (Tom Baker) and Romana uncover a plot to steal the Mona Lisa. Julian Glover. Duggan: Tom Chadbon. Countess: Catherine Schell. Kerensky: David Graham.

The Doctor is called in to investigate a pair of mysterious seed pods in the Antarctic. As the Doctor looks to uncover their mysteries, a ruthless collector arrives to add the seeds to his menagerie. Things take a turn when it is discovered that the pods harbor intelligent life with sinister plans of its own.

The Doctor discovers The Master's time machine.

The Doctor travels to 1925 Cranleigh Hall, where scarred hands are the only clue to a series of murders. Lady Cranleigh: Barbara Murray. Lord Cranleigh: Michael Cochrane.

The TARDIS is hijacked by Cybermen and taken to Telos, where the Doctor (Colin Baker) learns of the aliens' plan to invade Earth. Peri: Nicola Bryant. Lytton: Maurice Colbourne. Griffiths: Brian Glover. Russell: Terry Malloy.

A man named Elton is plunged into a world of living nightmares when he becomes obsessed with the Doctor, Rose and their mysterious blue box.

The Doctor plans to show Rose the London Olympics in 2012; a mother hides her daughter's unearthly powers.

The human race rejoices as ghosts of loved ones return home; an invasion force threatens modern day Earth.

Two mighty armies wage war across the Earth; terror emerges from beneath Torchwood Tower; the Doctor faces a dilemma.

No sooner has the Doctor said a tear-stained farewell to Rose Tyler than he finds himself face-to-face with a woman dressed in a fluffy white wedding frock. Who is she? Who is she supposed to be marrying? And how did she get on board the TARDIS?

The Doctor and Martha are transported into danger.

In Wales, items include a "Dr. Who" script and pottery.

Witches cast a spell on the Doctor and Martha.

The Doctor takes Martha to the planet New Earth in the future where the streets are ruled by sinister pharmacists.

Part 1. The TARDIS lands in 1930s New York, where people are disappearing from the streets.

Part 2. The Doctor forms a deadly alliance to save humanity.

Turning back the clock has consequences.

As a spaceship hurtles towards the sun, the Doctor and Martha have just 42 minutes to save the day.