Due to power shortages and staff breakdowns, work at a secret Derbyshire atomic research centre is being delayed. Some of the staff have been severely traumatised and end up in hospital drawing cave-markings on the walls. U.N.I.T. is called in, and the Doctor investigates the local cave system in Wenley Moor.
The Doctor discovers a group of reptilian creatures referred to as Silurians. (He later finds out this was incorrect). They were re-awoken by the power from the nuclear plant and plan to retake Earth as their home, and destroy all ape-life.
The Doctor attempts to negotiate a peace with the leader, and would have succeeded if it hadn't been for a younger rebellious Silurian seizing power, and releasing a deadly virus to kill off the humans. The Doctor manages to get hold of an antidote, and an epidemic is averted.
But the Silurians have another trick and plan to destroy the Earth's Van Allen Belt, which would make Earth more tolerable for them, but lethal to humans. The Doctor overloads the reactor, and the Silurians retreat underground. Much to the Doctor's dismay the Brigadier takes the opportunity to destroy the Silurians' cave.
Regular castBrigadier Lethbridge-Stewart: Nicholas Courtney; Liz Shaw: Caroline John;
Guest castDoctor Charles Lawrence: Peter Miles (1-6); Major Baker: Norman Jones (1-5); Miss Dawson: Thomasine Heiner (-5); Doctor John Quinn: Fulton MacKay (1-3); Doctor Meredith: Ian Cunningham (1-3); Roberts: Roy Brannigan (1); Spencer: John Newman (1); Davis: Bill Matthews (1); Captain Hawkins: Paul Darrow (2-7); Silurians: Paul Barton (4,5,7), Simon Cain (4-7), Dave Carter (4-5), John Churchill (4,5,7), Pat Gorman (2-4); Silurian Voice: Peter Halliday (2-7); Squire: Gordon Richardson (2); Doris Squire: Nancie Jackson (2); Young Silurian: Nigel Johns (4-7); Edward Masters: Geoffrey Palmer (4-6); Old Silurian: Dave Carter (4-5); Sergeant Hart: Richard Steele (4,6); Travis: Ian Talbot (4); Private Robins: Harry Swift (5); Silurian Scientist: Pat Gorman (5-7); Corporal Nutting: Alan Mason (6-7); Private Wright: Derek Pollitt (6-7); Hospital Doctor: Brendan Barry (6); Receptionist: Sheila Knight (1); Nurse: Gillian Toll (6);
Uncredited cast: Technicians: Keith Ashley, Terry Denville, Ronald Gough, Joan Harsvant, Peter Holmes, Richard King, Leonard Kingston, Stewart Myers, Cara Stevens, Cy Town; Soldiers: Alex Donald, Brian Haughton, Mark Johnson, David Melbourne, John Spradbury; Extras: Bernard Barnsley, Paul Barton, David Billa, Willy Bowman, Peter Brett, Constance Carling, Sue Casters, Hugh Cecil, Norton Clark, Alan Clements, Colin Cunningham, Alison Daumler, Jim Delaney, Josie Dent, Ray Denton, Antonio di Maggio, John Doye, Michael Earl, Bella Emberg, Mostyn Evans, Stenson Falcke, Keith Goodman, Pat Gorman, Paul Hawking, Walter Henry, Alan Hood, Harold Horsham, Jean Hylton, Nigel Johns, Barry Kennington, Joanna Lawrence, Michael Lomax, Iona MacCree, Olive Macneil, Alan Mason, Pat Matthews, Patrick Milner, Michael Moor, Maureen Nelson, Roy Pearce, David Perry, Derek Pollitt, Liz Powers, Ray Rashley, Peter Ray, Winifred Ray, Betty Richardson, George Romanoff, Jean Shannon, John Shorter, Brendan Skilton, Richard Steele, Rosina Stewart, Harry Swift, Lynn Turner, Alan Viccare, Joyce Windsor, Harold White;
|BBC 1||258||Episode One||Sat 31 January 1970||5:15 pm - 5:40 pm||8.8M||41st|
|BBC 1||259||Episode Two||Sat 7 February 1970||5:15 pm - 5:40 pm||7.3M||68th|
|BBC 1||260||Episode Three||Sat 14 February 1970||5:15 pm - 5:40 pm||7.5M||60th|
|BBC 1||261||Episode Four||Sat 21 February 1970||5:15 pm - 5:40 pm||8.2M||46th|
|BBC 1||262||Episode Five||Sat 28 February 1970||5:15 pm - 5:40 pm||7.5M||52nd|
|BBC 1||263||Episode Six||Sat 7 March 1970||5:15 pm - 5:40 pm||7.3M||63rd|
|BBC 1||564||Episode Seven||Sat 14 March 1970||5:15 pm - 5:40 pm||7.5M||54th|
Repeats (on the BBC)
Hankley Common; Marylebone Station, London; Milford Chest Hospital, Goldaming, Surrey; Transmitter Station, Hog's Back, Surrey;
Television Centre Studio 1; Television Centre Studio 3; Television Centre Studio 8;
Bloopers and mistakes
Watch Liz's belt - first it's tied on the right and then later it's tied on the left... And then back again!
Episode 1: At the beginning, when Liz stands up from kneeling, her belt gets caught on the bottom of her skirt and raises it up.
Notes and trivia
This story, an oddity due to it having "Doctor Who and..." in the title, is the first to feature Bessie, the Doctor's car.
This story was thought to be lost but now exists in a UK transmittable version obtained by merging the previously surviving black and white film prints and NTSC colour recordings.