The adventures of a Time Lord—a time-travelling humanoid alien known as the Doctor—who explores the universe in his TARDIS, a sentient time-travelling space ship. Its exterior appears as a blue British police box, which was a common sight in Britain in 1963 when the series first aired. Along with a succession of companions, the Doctor faces a variety of foes while working to save civilisations, help ordinary people, and right wrongs.
Knights from a parallel universe arrive on Earth to find the legendary sword Excalibur. And only the Doctor and Ace with the assistance of Brigadier Lethbridge Stewart and save the Earth from total catastrophe.
The Doctor and Ace discover a stone spaceship underneath Warmsley's archaeological dig while Mordred summons Morgaine to Earth's dimension.
The Brigadier rescues the Doctor from the stone spaceship before they set out to locate Morgaine before she gains Excalibur.
Morgaine forces Ace and Shou Yuing to hand over Excalibur by threatening to release the Destroyer, so the Doctor and the Brigadier enter a dimensional portal to stop her.
The Doctor take Ace to an old 'haunted' house called Gabriel Chase in the year 1883. 100 years before events that took place within that very house in her personal past.
The Doctor manages to rescue Ace from the husks and then tries to uncover the truth about the goings on in Josiah's house.
The Doctor attempts to convince Light to put an end to Smith's schemes but instead Light aims to put an end to Earth's evolution.
England, the 1940s. The TARDIS brings the Doctor and Ace to a secret naval base during WWII. There, the time-travellers battle vampiric Haemovores and an ancient Viking curse!
The Doctor and Ace manage to convince Sorin to release them while Millington and Judson attempt to translate the Viking runes.
The Doctor and his friends come under attack from the Haemavores, allowing Millington to retrieve the flask containing Fenric's essence.
Fenric is loose and planning to use the Ancient Haemovore to poison the Earth with chemicals, unless the Doctor can defeat him in their centuries old game.
Perivale, England, the late 1980s. People are vanishing into thin air under the baleful stare of a very strange cat. The Doctor and Ace learn that, in the battle for survival, success can carry a terrible price...
The Doctor and Paterson manage to escape from the Master and join up with Ace and her friends, where the Doctor tries to find a way to get them all off the planet before it explodes.
Ace manages to transport the Doctor and the others back to Perivale but the Master is also there, preparing for a final showdown with the Doctor.