But the current Keeper, his powers waning, senses some all-pervading evil about to invade his world. He summons the Doctor to his aid.

To save Traken the Doctor fights the terrifying Melkur - only to find that this new enemy conceals an older and even deadlier foe - one the Doctor has encountered before...
 

"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 ...

Produced by John Nathan-Turner
Directed by John Black
Running Time 98 mins approx
Cover Illustration: Andrew Skilleter