An antimatter creature has crossed into normal space via a phenomenon known as the Arc of Infinity but needs to bond physically with a Time Lord in order to remain stable.

A traitor on Gallifrey has chosen the Doctor as the victim.

The Doctor (Peter Davison) and Peri (Nicola Bryant) become embroiled in an underground war of gun running and drug smuggling shortly after landing on the planet Androzani Minor. Apprehended by the military, they are rescued from execution by brilliant but horribly disfigured criminal Sharaz Jek, whose infatuation with Peri looks set to be cut short when he discovers that both she and the Doctor have contracted the deadly disease Spectrox Toxaemia. The only possible cure is the milk of the queen bat, which dwells in the caves currently being roamed by the killer Magma Creature...

The Twin Dilemma is available on DVD in Regions 1, 2 & 4.

A race of giant gastropods has taken over the planet Jaconda. Their leader, Mestor, now intends to cause an enormous explosion in order to spread his people's eggs throughout the galaxy, and he kidnaps juvenile twin geniuses from Earth to work out the necessary mathematical equations.

Space fighters led by Lieutenant Hugo Lang are dispatched to get the twins back, but they come under attack and Lang is the sole survivor when his ship crashes on the asteroid Titan 3.

The TARDIS is lured to Earth, London, 1985 by an alien distress signal. Investigating, the Doctor and Peri stumble upon an attempted bank robbery staged through the London sewers by a familiar foe – ex-Dalek agent, Lytton. But who is he working for this time?

For they soon discover there is something far nastier lurking in the sewers – Cybermen.

Why do the silver giants need a time machine? What is their devastating plan of attack? And what does it have to do with a catastrophic event that happened long ago in the Doctor’s past?

Vengeance on Varos is available on BBC DVD: In a regular edition and as a, features and extras packed, Special Edition (Regions 1, 2 & 4)

The Doctor visits the planet Varos to obtain supplies of a rare ore called zeiton 7, vital to the functioning of the TARDIS. Varos was once a colony for the criminally insane and the descedants of the orginal guards still rule over the rest poverty-striken population.

The Doctor and Peri meet two rebels, Jondar and Areta, and Peri and Areta are captured by Qullam, the Dome's sadistic commandant...

Starring Colin Baker, Nicola Bryant. Written by Phillip Martin. Directed by Ron Jones. Produced by John Nathan-Turner.

Another adventure for everyone's favourite Time Lord. The Doctor (Colin Baker) and Peri arrive in the north of England during the Luddite uprisings, and discover that brilliant but amoral Time Lord the Rani is stealing the chemical which promotes sleep from the mine workers' brains. The Master is also in town, planning to use the disruptive Luddites to deprive the Doctor of his TARDIS and destroy him once and for all.

Starring: Peter Childs, William Ilkley, Terence Alexander, Colin Baker, Hus Levent, Kate O'Mara, Nicola Bryant, Gary Cady, Richard Steele, Gawn Grainger, Anthony Ainley. Directed by: Sarah Hellings.

When the Doctor (Colin Baker) lands on a space station in the Third Zone, he suspects he's been there before and when he discovers his old assistant - Jamie - he's certain. Accompanied by Jamie and his present assistant Peri, the Doctor follows himself (Patrick Troughton) to 20th Century Seville. There he discovers his old enemeies, the Sontarans, about to dissect him in a genetic operation. But just why are they operating on the Doctor? And how will their findings aid their enslavement of the universe? Deadly questions to which the Doctors must find answers in order to escape their own excruciating death...

Starring: Patrick Troughton, Colin Baker, Nicola Bryant. Directed by: Peter Moffatt

On the planet Karfel a high ranking official, Maylin Tekker, uses threats against Peri to force the Doctor (Colin Baker) to go to Earth and bring back a young woman called Vena who, while holding a precious amulet, has accidentally fallen into the Timelash - a time tunnel through which the planets tyrannical ruler the Borad banishes all rebels.

The Doctor also inadvertently brings back Herbert, a man from the 19th Century, who stows away aboard the TARDIS.

The Doctor and Peri arrive on Necros to attend the funeral of an old friend of the Doctor who has recently died. However, Tranquil Repose is not all it seems and an attempt is made on the Doctor's life. Soon the Doctor comes face to face with the Great Healer, only to discover it is none other than Davros, the creator of the Daleks, intent on rebuilding the Dalek race decimated by the Movellans.

The TARDIS is drawn to a space station where the Doctor is subjected to a Time Lord inquiry into his behaviour, presided over by an Inquisitor. The prosecuting counsel, the Valeyard, presents the first piece of his evidence, which consists of a recording played back on a screen linked to the Matrix. It concerns a visit by the Doctor and Peri to the desolate planet Ravolox...