When the TARDIS lands in a quarry on Earth, Sarah unearths what appears to be a fossilised hand, buried in one-hundred-fifty-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...

Cast:Tom Baker, Elisabeth Sladen, Stephen Thorne, Judith Paris, Roy Pattison, Roy Skelton,

Genre:Science Fiction, Drama, Adventure,

country:United Kingdom,

Production:BBC,