Starring Jon Pertwee as the Doctor and Katy Manning as Jo Grant.
UNIT is called in after a miner from the Welsh village of Llanfairfach is found dead, his skin glowing bright green. Jo joins forces with a local environmental group, led by Professor Clifford Jones, while the Doctor investigates the nearby plant of a company called Global Chemicals.
They discover that the mine workings are full of giant maggots and green slime – both lethal to touch – that have been produced by chemical waste pumped from the Global plant.
Cover signed by Katy Manning