While the Doctor indulges his wanderlust with a brief trip to Metebilis 3, the Brigadier of Jo Grant drive to South Wales to investigate the death of a miner at a disused pit owned by the mysterious Global Chemicals. The most astonishing symptom of the minor's fatal disease is the it leaves the skin bright green. The Doctor arrives on the scene and soon suspects that the Global Chemicals factory management may have something to hide. When he and Jo Discover a vast green lake teeming with deadly giant maggots hidden in the abandoned mine, he fears the threat may have already reached global proportions.
- Audio Commentary by actor Katy Manning, producer Barry Letts and script editor Terrance Dicks
- Interviews with visual effects designer Colon Mapson, writer Robert Sloman, actor Stewart Bevan (Clifford Jones)
- "Global Conspiracy!" mockumentary
- Photo gallery
- Production Notes