In the distant future, the Doctor, Sarah and Harry find a space station preserving the future of mankind. But the insect Wirrn have got there first...
Tom Baker
The Doctor
Elisabeth Sladen
Sarah Jane Smith
Ian Marter
Harry Sullivan
Wendy Williams
Vira
Kenton Moore
Noah
Richardson Morgan
Rogin
John Gregg
Lycett
Christopher Masters
Libri
Stuart Fell
The Wirrn
Nick Hobbs
Gladys Spencer
High Minister (voice)
Peter Tuddenham
Voices on Nerva (voice)
