18th December 1974 – 18th January 1975
You may be a Doctor, but I’m the Doctor: the definite article, you might say…
The Doctor to Harry Sullivan, episode 1
After ten years and three identities, British television’s early evening science-fiction hero, Doctor Who faced one of his gravest challenges in 1973. Confronting a giant spider in a cave bathed by lethal radiation, the third Doctor (Jon Pertwee) willingly sacrificed his life to thwart this creature’s insane ambitions of universal domination.
Stumbling back to Earth a radiation-ravaged Doctor is saved from imminent death only by his Time Lord powers of bodily regeneration. Observed by friends Sarah Jane Smith (Elisabeth Sladen) and Brigadier Lethbridge-Stewart (Nicholas Courtney), the Doctor’s familiar greying temples and craggy features blur and change, revealing the face of a younger man with piercing blue eyes and dark, curly hair; the face of the fourth Doctor Who.
But the Brigadier has a new problem: the theft of government construction drawings and components for a deadly disintegrator gun. Barely recovered from his regeneration, the Doctor, aided by Sarah and Surgeon-Lieutenant Harry Sullivan, confront the Scientific Reform Society – a partnership of power-hungry scientists backed up by a robot of frightening size and strength. As a threat of nuclear armageddon looms, the Doctor’s only hope of saving planet Earth is to refine and deploy a metal eating virus that will destroy both the robot and its disintegrator weapon before countdown reaches zero.
Video © BBC