The TARDIS materialises on a planet where the Earth colony is run more like a holiday camp. The Doctor learns from a man named Medok that at night the colony is being infiltrated.
The Doctor finds that the infiltrators are in fact the Macra who have taken over the human colonists and are using them to mine gas that is necessary for their survival.
The Doctor is imprisoned, and Ben falls under the influence of the Macra. It is left to Jamie and Polly to free the others before they to succumb to the Macra.
Under the guidance of the Doctor, Ben destroys the gas pumping equipment, destroying the Macra and freeing the colonists.
Regular castBen Jackson: Michael Craze; Polly Wright: Anneke Wills; Jamie McCrimmon: Frazer Hines;
Guest castPilot: Peter Jeffrey; Ola: Gertan Klauber; Controller: Graham Leaman; Macra Operator: Robert Jewell; Medok: Terence Lodge (1-3); Control Voice: Denis Goacher (1-3); Broadcast Voice: Richard Beale (1-3); Sunnae: June Enshawe (1,4); Chicki: Sandra Bryant (1); Drum Majorette: Maureen Lane (1,4); Alvis: Anthony Gardner (1); Barney: Graham Armitage (1); Questa: Ian Fairbarn (1); Official: John Harvey (3-4); Guards: (all 4) John Caeser, Steve Emerson, Danny Rae; Cheerleaders: (all 4) Ralph Carrigan, Roger Jerome, Terry Wright;
Uncredited cast: Pilot's Secretary: Linda Reynolds; Scientist: Paul Philips; Girl: Nina Huby; Band: Fiona Frazer, Avril Gaynor, Maris Hendrick, Janice Hoy, Jill Paris, Amanda Scott; Dancers: Joe Finlay, Maureen Hillman, Sheelah McGrath, Ted Merwood, Judy Nichols, Anthony Rayner; Citizens: Bill Beesley, Deryn Fisher, George Gibbs, Edwina King, Leonard Kingston, Maureen Morris, Leslie Pitt; Mine Workers: Walter Henry, Maureen Hillman, Leonard Kingston, Sheelah McGrath, Judy Nichols, Anthony Rayner, Tony Starr, Alan Troy;
|BBC 1||153||Episode 1||Sat 11 March 1967||5:50 pm - 6:15 pm||8.0M||37th|
|BBC 1||154||Episode 2||Sat 18 March 1967||5:50 pm - 6:15 pm||7.9M||42nd|
|BBC 1||155||Episode 3||Sun 26 March 1967||5:50 pm - 6:15 pm||8.8M||45th|
|BBC 1||156||Episode 4||Sat 1 April 1967||5:50 pm - 6:15 pm||8.4M||39th|
Brighton Rubbish Tip, East Sussex; Dunstable;
Ealing Television Film Studios; Lime Grove Studio D;
Bloopers and mistakes
This programme has no bloopers or mistakes. It's probably not perfect, just that they haven't been found or pointed out yet.
Notes and trivia
This story was the first to use a new title sequence, again by an uncredited Bernard Lodge.