Britain is full of hidden wilderness. Our explorers and authors are forever rediscovering it. In recent years Richard Mabey, Robert Macfarlane and even Bear Grylls have searched the country for somewhere truly wild. Paul Binding finds it in the Berwyn Mountains in northeast Wales, where tradition sites Annwn, the otherworld of Welsh mythology.

This is where Nat Kempsey goes missing the summer after his A-levels, until he is rescued six days later. His father, Peter, vanished briefly in the same stretch of countryside thirty-five years earlier. The parallel is curious enough for a local journalist to pay the pair a visit. As the