Katherine Jenkins travels to Boverton in the Vale of Glamorgan to tell the story of a remarkable find of Iron Age jewellery. Bettany Hughes visits the Isle of Wight to meet the girl who uncovered a 5,000-year-old tool while on a school trip, and Mary-Ann Ochota dives for treasure at the site of the sunken HMS Colossus off the Isles of Scilly. Last in the series.