Doctor Who and the Green Death

The Green Death begins slowly. In a small Welsh mining village a man emerges from the disused colliery covered in a green fungus. Minutes later he is dead. Unit, Jo Grant and Doctor Who in tow, arrive on the scene to investigate, but strangely reluctant to assist their enquiries is Dr Stevens, director of the local refinery Panorama Chemicals.

Are they in time to destroy the mysterious power which threatens them all before the whole village, and even the world, is wiped out by a deadly swarm of green maggots?