When the TARDIS lands in on Earth in a quarry, the Doctor and Sarah are caught in a mining explosion. She is found clutching what appears to be a fossilised hand, buried in 150 million-year-old strata. Analysis shows the hand to be silicon-based and inert, but when Sarah begins to act as if possessed, the Doctor suspects that it may still be alive... Originally transmitted on BBC1 2 October to 23 October 1976.
Audio commentary by Tom Baker (the Doctor), Elisabeth Sladen (Sarah Jane Smith), Judith Paris (Eldrad), Bob Baker (co-writer), Philip Hinchcliffe (producer)
'Changing Times': a documentary charting the special relationship between the Doctor and his companion Sarah Jane Smith (50 mins)
A very rare clip of Tom Baker and Elisabeth Sladen's appearance on the first ever edition of Noel Edmonds' Multi-Coloured Swap Shop, shown in October 1976
Photo gallery
Continuity announcements
Information text subtitles
1977 Doctor Who Annual (pdf format)
Radio Times listings (pdf format)
Easter Egg (hidden feature)