Investigating Loch Ness, the Doctor (Tom Baker) makes Zygons be bygones. Tom Baker, Elisabeth Sladen. Benton: John Levene. Munro: Hugh Martin. Duke: John Woodnutt.

The Doctor (Tom Baker) returns to Gallifrey to become President. Louise Jameson. Vardan Leader: Stan McGowan. Andred: Chris Tranchell.

The Doctor and Adric learn from the wizened Keeper of Traken that a great evil has come to his planet in the form of a Melkur - a calcified statue. The Keeper is nearing the end of his reign and seeks the Doctor's help in preventing the evil from taking control of the bioelectronic Source that is the keystone of the Traken Union's civilisation.

The TARDIS arrives on a planet where a savage tribe called the Sevateem worship a god called Xoanon. The Doctor discovers that Xoanon is in fact a spaceship computer that he tried to repair at some point in his past and inadvertently drove mad by giving it a multiple personality.

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.

After the Doctor and his friends are exposed to a strange plague, Sarah becomes infected. Meanwhile, the Cybermen plan to destroy the planet of gold. Tom Baker, Elisabeth Sladen. Tyrum: Kevin Stoney.

The Fendahl gains power by absorbing the life force of humans. Tom Baker, Louise Jameson. Adam Colby: Edward Arthur. Fendelman: Denis Lill. Thea: Wanda Ventham.

The tracer brings the TARDIS to the planet Tara. Romana is taken prisoner by Count Grendel.

The Doctor employs ancient powers to overcome the Fendahl. Louise Jameson. Jack Tyler: Geoffrey Hinsliff. Martha: Daphne Heard. Thea: Wanda Ventham. Adam Colby: Edward Arthur. Ted Moss: Edward Evans.

One morning in every city and town in the world, the human race wakes up to face the most surprising invasion yet. Everywhere, in every land, a forest has grown overnight and taken back the Earth. It doesn t take the Doctor long to discover that the final days of humanity have arrived.

The Doctor's worst enemies, The Daleks, The Cybermen, The Angels and The Silence, return, as the doctor's eleventh life comes to a close, and his twelfth life begins.

The Doctor and a newly-regenerated Romana arrive on Skaro and discover that the Daleks are using explosive charges and a group of humanoid slave workers to mine the planet in search of their creator, Davros. A stalemate has arisen in an interplanetary war that the Daleks are waging against the robotic Movellans, and their hope is that Davros will be able to give them the edge.

The TARDIS falls through a CVE into E-Space and arrives on the planet Alzarius. There the inhabitants of a crashed Starliner and a group of young rebels called the Outlers, led by a boy named Varsh and including his brother Adric, are being terrorised by a race of Marshmen who emerge from the marshes at a time known as Mistfall.

Monarch provides entertainment featuring android replicas of earthlings. Dr. Who: Peter Davison. Adric: Matthew Waterhouse. Bigon: Philip Locke. Nyssa: Sarah Sutton.

The Doctor and Donna visit Pompeii in AD 79, on the eve of the eruption of Mount Vesuvius.

The Doctor takes Donna to her first alien world, but the Ood-Sphere reveals some terrible truths about the human race.

Part 1. Sontaran warriors set their sights on the Earth and its inhabitants.

Part 2. As poison gas suffocates the Earth's population, the Doctor and UNIT team members work to eliminate the threat.

The Doctor meets the most important woman of his life.

Agatha Christie's 10-day disappearance in 1926 may have been the result of amnesia, a nervous breakdown, or a giant alien wasp.

The overlap between quantum reality and science fiction is discussed.

Part 1. The Doctor and Donna must uncover the truth behind the Nodes and the Data Ghost to uncover the library's secret.

Part 2 . As the shadows rise, the Doctor forges an alliance with the mysterious River Song.

The Doctor is trapped, powerless and terrified, on the planet Midnight, as a knocking on the wall begins.

Donna gets help from a mysterious blond woman.

Part 1. Earth's greatest heroes assemble to fight the New Dalek Empire, but a fearsome old enemy waits in the shadows.

Part 2. As Davros and the Daleks threaten the entire universe, the Doctor's companions join forces. However, the prophecy declares that one of them will die.

It's the Tenth Doctor's final journey - but his nemesis, The Master, has been reborn. A terrible shadow falls across the Universe as great danger approaches, and the Doctor faces the end of his life as the Master's plans hurtle out of control.

In the mysterious world of the Nethersphere, plans have been drawn. Missy is about to come face to face with the Doctor, and an impossible choice is looming… “Death is not an end” promises the sinister organization known only as 3W – but, as the Doctor and Clara discover, you might wish it was.