While the Doctor plans a holiday to Metebelis Three, Jo and the Brigadier are intrigued by a mysterious death at a coal mine in Llanfairfach, which is being blamed on local company Global Chemicals.
Did You Know?
Some of the real maggots used in certain scenes rapidly turned into Blue Bot Flies due to heat from the lamps being used to light the sets. See more
When Dai is alone down the mine, telephoning for help, a crew member's arm is clearly visible moving in the bottom right corner of the screen. He may be signalling the actor to start. See more
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