The TARDIS narrowly avoids becoming engulfed in a cobwebby substance in space. It arrives in the London Underground railway system, the tunnels of which are being overrun by the web and by the Great Intelligence's robot Yeti. The time travellers learn this crisis was precipitated when Professor Travers, whom they first met in the Himalayas some thirty years earlier, accidentally caused one of the Yeti to be reactivated, opening the way for the Intelligence to invade again.

Genres

Cast

Patrick Troughton

The Doctor

Frazer Hines

Jamie McCrimmon

Deborah Watling

Victoria Waterfield

Nicholas Courtney

Colonel Lethbridge-Stewart

Jack Watling

Professor Travers

Stephen Whittaker

Craftsman Weams

John Levene

Yeti

Jeremy King

Yeti