On the planet Tigella, the mysterious source of all power - the Dodecahedron - is failing. Zastor, the leader of the planet, decides to call on an old friend to help them. An old friend who travels the universe in a blue police box.

The Fourth Doctor departs, the Fifth arrives and the Master returns in these three classic 1980s adventures!

When the Doctor (Peter Davison) tries to take Tegan (Janet Fielding) back to Heathrow Airport, the Tardis arrives in the 17th century instead of the 20th century. The time-travellers discover that a space capsule has landed nearby and its alien occupants intend to wipe out life on Earth by releasing rats infected with a great plague.

All 12 episodes of the Black Guardian trilogy from the twentieth season of the long-running sci-fi series. On discovering public schoolboy Turlough lost aboard an apparently abandoned cruiser in space, the Doctor (Peter Davison) transports to Earth in 1983, only to meet up with his old friend friend and UNIT colleague, Brigadier Lethbridge-Stewart, who has apparently lost all memory of him. Back in 1977, Tegan and Nyssa meet the younger Brigadier and a disfigured alien they believe could be a regenerating Doctor. However, it turns out that this is all in fact part of a plot to destroy the Doctor by the Black Guardian, who has made a deal with Turlough to grant him transportation away from Earth if he kills the Doctor. Episodes are: 'Mawdryn Undead (Parts 1-4)', 'Terminus (Parts 1-4)' and 'Enlightenment (Parts 1-4)'.