More highlights of last year's series, reconstructed with the emergency services, actors and the people involved in the original rescues. This week: how a Sunday-afternoon stroll turned into a desperate struggle against time and tide. Two potholers get into trouble while negotiating the "black hole" 500 feet beneath the Mendip Hills. Two men on a fishing trip are at the centre of a massive search and rescue operation in the Bristol Channel. And how a Somerset farmer fought his way back to health after a tractor accident left him with a broken back.