Hugh Dennis and the team are in Odiham, Hampshire, searching for the house of Sir Frances Walsingham, the head of Elizabeth I's Secret Service. It is the first time the site has ever been dug, so with very little to go on, our team want to locate the house, work out its size and scale, and what Walsingham may have used it for. As part of the investigation, Hugh turns his hand to spy craft as he learns how Walsingham used to break codes.

Hugh Dennis and the team solve a 17th-century mystery in King's Lynn, as they hunt for enormous defensive earthworks that surrounded the Norfolk town during the English Civil War. However, as the barricades were built from Earth and the team are looking for them in Earth, finding any evidence of their existence is not going to be easy.