The TARDIS materialises on board a space station. Everything is fully automated, including defence systems, and the station seems to be deserted, until the Doctor and Harry find a room full of humans held in suspended animation - and also the body of a dead Wirrrn.
One of the bodies is missing, and when of the people are revived, the Doctor and Harry are accused. Meanwhile, Sarah laid down on a bench, and was teleported to the cryogenic facility.
Investigations by the Doctor find that the station has been invaded by the Wirrrn. The Wirrrn had damaged the machinery that controlled the de-freeze process, hence the people failed to awaken at the right time.
The Wirrrn had been using the people as food. The humans' leader, Noah, was assimilated by the Wirrrn, giving them access to all his memories. The Doctor used this to convince Noah, who was now a Wirrrn himself, to take the Wirrrn outside the space station. When the shuttlecraft's engines were fired the Wirrrn were destroyed.
The original idea was for the people on board the space station to return to Earth when the solar flares had calmed down. The transporter was not functioning properly, and the Doctor offered to go down to Earth and fix the problem.
Regular castSarah Jane Smith: Elisabeth Sladen; Harry Sullivan: Ian Marter;
Guest castVoices: Gladys Spencer (1,3), Peter Tuddenham (1); Vira: Wendy Williams (2-4); Noah (Lasar): Kenton Moore (2-4); Libri: Christopher Masters (2); Rogin: Richardson Morgan (3-4); Wirrrn Operators: Stuart Fell (3-4), Nick Hobbs (4); Lycett: John Gregg (3);
Uncredited cast: Dune: Brian Jacobs (1,3); Wirrrn Grub: Stuart Fell (2-3); Bodies in Palletts: Richard Archer, Geoff Brighty, Rick Carroll, Sean Conney, Peter Duke, Jan Goram, Brian Jacobs, Tina Roach, Lynn Summer, Barry Summerford;
|BBC 1||386||Part One||Sat 25 January 1975||5:35 pm - 6:00 pm||9.4M||27th|
|BBC 1||387||Part Two||Sat 1 February 1975||5:30 pm - 5:55 pm||13.6M||5th|
|BBC 1||388||Part Three||Sat 8 February 1975||5:30 pm - 5:55 pm||11.2M||17th|
|BBC 1||389||Part Four||Sat 15 February 1975||5:30 pm - 5:55 pm||10.2M||24th|
Repeats (on the BBC)
This programme does not have any outside filming
Television Centre Studio 1; Television Centre Studio 3;
Bloopers and mistakes
Episode 1: Watch out for Liz Sladen's knickers. They appear when Harry and the Doctor lift Sarah onto a couch to recover from her fit of suffocation, and as she is lifted her dress flaps down at the back, showing a brief glimpse of her knickers. Liz Sladen later said that she regularly used to receive requests by post for those particular undies.
Notes and trivia
Part Two of this story achieved the highest ever ratings position for Doctor Who - 5th!
This programme has no other working titles, or they have not been yet been entered.