The Green Death is the fifth and final serial of the tenth season of the British science fiction television series Doctor Who, which was first broadcast in six weekly parts on BBC1 from 19 May to 23 June 1973. It was the last regular appearance of Katy Manning as companion Jo Grant. In the serial, the alien time traveller the Third Doctor (Jon Pertwee) and the organisation UNIT investigate a South Wales mine where waste from an oil plant has killed miners and made maggots grow to giant size. Plot The Third Doctor is making adjustments to the TARDIS' coordinate programmer in preparation for a visit to Metebelis Three, when Jo reads in a newspaper about the mysterious death of a miner named Hughes in the abandoned coal mine in Llanfairfach in South Wales. The miner was found dead and glowing bright green. Brigadier Lethbridge-Stewart and Jo go down to investigate the miner's death. The Doctor agrees to follow the Brigadier, but is determined to go to Metebelis Three first. The Brigadier's first port of call is the recently opened Global Chemicals oil plant, close to the abandoned mine. Its headman, Stevens, claims that the plant can "produce 25% more petrol and diesel fuel from a given quantity of crude oil"—but that the 'Stevens process' only produces a minimal amount of waste. Local environmental scientist Professor Cliff Jones is convinced that the oil-making process must create thousands of gallons of waste. He also believes that there is a link between Global Chemicals and Hughes' death—but his research is too demanding for him to go down the mine and investigate. Jo heads for the mineshaft. The Doctor reaches Metebelis Three, but it is far from the "blue paradise" he described. He is attacked by various unseen creatures, and returns to the UNIT laboratory with only a small blue crystal to show for his misadventure. He then drives down to South Wales in his car, Bessie, and meets the Brigadier at Global Chemicals. They then set off to go down the mine to investigate, despite Stevens' insistence that it should be sealed. Stevens summons his henchman, Hinks, and tells him in a strange emotionless voice "nobody must go down the mine". Hinks leaves and Stevens dons a pair of strange headphones. Jo has arrived at the pithead ahead of the Doctor and the Brigadier, and gone down the shaft with a miner