While investigating a vanishing Concorde at Heathrow Airport, the Doctor and his companions are thrown millions of years back in time, when a mysterious alien called Kalid is trying to control the ancient powers of the Xeraphin.

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Main Cast: Peter Davison, Sarah Sutton, Janet Fielding, Anthony Ainley, Nigel Stock, Richard Easton, Keith Drinkel, Michael Cashman, John Flint, Judith Byfield

Director: Ron Jones

Writer: Peter Grimwade

Editors: Rod Waldron, Mike Houghton

Cinematographer:

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