The Doctor and UNIT investigate a deadly infection lurking underneath the Welsh mining town of Llanfairfach. It's an adventure that will change Jo Grant's life forever...
Jon Pertwee
The Doctor
Katy Manning
Jo Grant
Nicholas Courtney
Brigadier Lethbridge-Stewart
John Levene
Sergeant Benton
Richard Franklin
Captain Mike Yates
Stewart Bevan
Cliff Jones
Jerome Willis
Stevens
Tony Adams
Elgin
Ben Howard
Hinks
Mostyn Evans
Dai Evans
Talfryn Thomas
Dave
Roy Evans
Bert
Mitzi McKenzie
Nancy
Ray Handy
Milkman
John Scott Martin
Hughes
John Rolfe
Fell
John Dearth
BOSS (voice)
Richard Beale
Minister of Ecology
Jean Burgess
Cleaner
Brian Justice
Yates' Guard
Terry Walsh
Guard
Roy Skelton
James
Robert Sloman
Writer
Michael E. Briant
Director
Michael McDermott
Production Assistant
Terrance Dicks
Script Editor
Barbara Kidd
Costume Design
Dudley Simpson
Original Music Composer
John Harris
Barry Letts
Producer
Stunt Coordinator
Dick Mills
Special Sound Effects
Alastair Mackay
Editor
Ken Lowe
Camera Operator
John Burrowes
Production Design
Simon Wilson
Sound
Mike Jefferies
Lighting Director
Ann Rayment
Makeup Artist
Richard Chubb
Bill Matthews
Ron Oates
Visual Effects Designer
Delia Derbyshire
Theme Song Performance
