Season 7

(4 episodes)

As punishment for breaking the laws of time, the Time Lords have forced the Doctor to change his appearance, taken away his ability to time travel, and exiled him to Earth... But as the TARDIS arrives, so does a meteor shower carrying an alien invasion force.

Written by Robert Holmes

(7 episodes)

Exiled to Earth and now working for UNIT as their scientific advisor, the Doctor is summoned to an underground research centre at Wenley Moor to investigate a series of inexplicable power losses. Initially suspecting sabotage, he soon discovers that the nearby cave system conceals a colony of an ancient reptilian race called the Silurians. Awaking from a hibernation which has lasted millions of years, they are now intent on reclaiming the Earth from Mankind...

Written by Malcolm Hulke

(7 episodes)

Something has gone seriously wrong with Mars Probe 7. With no contact from the astronauts since the rocket started its return journey from Mars, Space Control is now extremely worried about the fate of the crew. A rescue mission recovers something, but whatever it is, it certainly isn't human. To find out what has happened to the astronauts, the Doctor must head into space without the TARDIS...

Written by David Whitaker, Malcolm Hulke, Trevor Ray and Terrance Dicks

(7 episodes)

Inferno is a top-secret project that involves drilling down into the crust of the Earth to unleash a new energy source. However, the Doctor, along with his assistant Liz Shaw, is concerned that this drilling will have disastrous consequences for the whole world. His concerns are soon confirmed when the TARDIS throws him into a dangerous parallel universe, where Project Inferno is almost complete and the end of the world is near...

Written by Don Houghton