This is an account of a significant event in British caving history, and a film that has become legendary in caving folklore. It features two divers, Geoff Yeadon and Oliver Statham (aka Bear), who over several years explored and plotted the caving system beneath the moors of Ingleborough before completing the dive from Keld Head to West Kingsdale Master Cave, beneath Ingleborough in North Yorkshire, on January 16th 1979.