“The power of the Keeper is almost ours. Only the Doctor can destroy all that we have planned. He must be found!”
The empire of Traken has lived in total harmony for over a thousand years, governed by the sacred Keeper and his loyal consuls. Until now. Fading fast, the Keeper calls the Doctor and Adric to Traken, fearing the impending disintegration of his world and the onset of a terrible evil. For the malignant presence of the Melkur lurks close by, growing stronger, plotting to replace the Keeper upon his death.
The Doctor must stop it before it gains control of the Source – the energy that sustains the very life of the planet. But just who is controlling the Melkur? The Doctor smells a rat of the very oldest kind…
Originally transmitted 31st January – 21st February 1981, this four part adventure starring Tom Baker brings a new assistant – Nyssa – for the Doctor.