The Doctor is exiled to Earth after being put on trial by his own people, the Time Lords. Stranded without the TARDIS, he is reunited with Lethbridge-Stewart and assists U.N.I.T. in investigating extraterrestrial threats.
The Doctor receives help from Liz Shaw to stop the Auton invasion of Earth, where living plastic is used as a weapon. During their adventures, they also uncover the Silurians - scientifically advanced reptilian humanoids who once ruled the Earth.






The TARDIS takes the newly regenerated Doctor to Earth to begin his exile.
A recovered Doctor escapes the hospital and joins UNIT in their investigation.
Sam Seeley has found one of the meteorites but the Autons want it back and are closing in.
The invasion begins as Auton shop dummies come to life and attack the public.
UNIT are summoned to Wenley Moor research station which is experiencing mysterious power losses.
Investigating the caves, the Doctor is attacked by a dinosaur-like creature.
The creature from the caves, wounded and dangerous, is on the loose on Wenley Moor.
Fearful of a war breaking out between the Silurians and mankind, the Doctor attempts to make peace.
When the Silurian leader is killed, all hopes of peace are lost.
As the Silurian plague quickly spreads, the Doctor desperately searches for a cure.
With the antidote to the plague found, the Silurians retaliate and take over the research centre.
UNIT is called in and the Doctor learns that someone is sending messages to the vessel.
Recovery 7 has returned to Earth but the UNIT convoy transporting the capsule is ambushed.
The recovery capsule is empty with the astronauts seemingly kidnapped.
Liz has been captured by Reegan who is holding the three aliens captive.
The Doctor prepares to pilot the Recovery 7 ship into space, but Reegan sabotages the fuel supply.
On board a vast spacecraft, the Doctor meets the alien captain who demands the return of the ambassadors.
General Carrington is behind the kidnapping of the ambassadors and intends to turn the world against the aliens.
UNIT are at a project run by Professor Stahlman who intends to penetrate Earth's crust.
The green slime oozing from the drill head is transforming men into monsters.
Transported to a parallel world, the Doctor discovers that England is under military rule.
In the parallel world, the drilling project is about to penetrate the Earth's crust.
In the parallel world, Earth’s crust has been penetrated, releasing terrible forces from within the Earth.
As the parallel Earth faces destruction, the Doctor is desperate to return to his world to warn them of the danger.
The Doctor has escaped the doomed, parallel Earth and attempts to put a halt to the drilling project.
Third Doctor
Jon Pertwee
Liz Shaw
Caroline John
Alistair Gordon Lethbridge-Stewart
Nicholas Courtney
Channing
Hugh Burden
Seeley
Neil Wilson
Mullins
Talfryn Thomas
Captain Munro
John Breslin
Dr. Henderson
Antony Webb
Nurse
Helen Dorward
Corporal Forbes
George Lee
UNIT Officer
Tessa Shaw
Technician
Ellis Jones
Wagstaffe
Alan Mitchell
2nd Reporter
Prentis Hancock
Major General Scobie
Hamilton Dyce
Dr Beavis
Henry McCarthy
Hibbert
John Woodnutt
Ransome
Derek Smee
Meg
Betty Bowden
Sergeant
Clifford Cox
Attendant
Edmund Bailey
Dr. Quinn
Fulton Mackay
Major Baker
Norman Jones
Dr. Lawrence
Peter Miles
Miss Dawson
Thomasine Heiner
Dr. Meredith
Ian Cunningham
Roberts
Roy Branigan
Spencer
John Newman
Davis
Bill Matthews
Third Doctor
Jon Pertwee
Liz Shaw
Caroline John
Alistair Gordon Lethbridge-Stewart
Nicholas Courtney
Captain Hawkins
Paul Darrow
Doris Squire
Nancie Jackson
Masters
Geoffrey Palmer
Sergeant Hart
Richard Steele
Travis
Ian Talbot
Old Silurian
Dave Carter
Young Silurian
Nigel Johns
Private Robins
Harry Swift
Silurian Scientist
Pat Gorman
Corporal Nutting
Alan Mason
Private Wright
David Pollitt
Hospital Doctor
Brendan Barry
Third Doctor
Jon Pertwee
Liz Shaw
Caroline John
Alistair Gordon Lethbridge-Stewart
Nicholas Courtney
Ralph Cornish
Ronald Allen
Taltalian
Robert Cawdron
Carrington
John Abineri
Van Lyden
Ric Felgate
John Wakefield
Michael Wisher
Miss Rutherford
Cheryl Molineaux
Grey
Ray Armstrong
Collinson
Robert Robertson
Quinlan
Dallas Cavell
Control Room Assistant
Bernard Martin
Dobson
Juan Moreno
Corporal Champion
James Haswell
Unit Sergeant
Derek Ware
Reegan
William Dysart
Lennox
Cyril Shaps
Heldorf
Gordon Sterne
Flynn
Tony Harwood
John Benton
John Levene
Private Parker
James Clayton
Control Room Assistant
Joanna Ross
Control Room Assistant
Carl Conway
Technician
Roy Scammell
Alien Space Captain
Peter Noel Cook
Michaels
Neville Simons
Lefee
Steve Peters
Private Johnson
Geoffrey Beevers
Professor Stahlman
Olaf Pooley
Sir Keith Gold
Christopher Benjamin
Greg Sutton
Derek Newark
Petra Williams
Sheila Dunn
John Benton
John Levene
Private Latimer
David Simeon
Private Wyatt
Derek Ware
Harry Slocum
Walter Randall
Bromley
Ian Fairbairn
Third Doctor
Jon Pertwee
Liz Shaw
Caroline John
Alistair Gordon Lethbridge-Stewart
Nicholas Courtney
RSF Sentry
Roy Scammell
Section Leader Elizabeth Shaw
Caroline John
Alistair Gordon Lethbridge-Stewart
Nicholas Courtney
Patterson
Keith James