The power struggle between Brigadier Lethbridge-Stewart and the unauthorized corporate operation run by Ralph Stevens, culminating in UNIT's reluctant involvement in Stevens' hazardous containment measures

The Brigadier returns to Llanfairfach Colliery with UNIT engineers and explosives, determined to seal the mine to contain the maggot infestation. Committed to a military solution, he orders demolition charges …

Stevens confronts the Doctor with cold finality after the mine detonation, dismissing him with a veiled threat of future violence. Recognizing Yates as a liability, Stevens orders him confined under …

In Jones’ cluttered lab, the Doctor and Jo examine grotesque larval samples under flickering fluorescents. Jones deduces that oil waste from Global Chemicals has triggered an atavistic mutation in the …