Richards uncovers the mysteries of the recently-discovered missing city of Calleva Atrebatum in Hampshire. All that now remains of it is a wall enclosing 100 hectares of empty fields, but with advanced computer graphics to fill in the gaps, the programme rebuilds Calleva, asking why it was abandoned. Supported by current findings, it proves that in its time, Calleva was a city of significance and then goes in search of the reasons for its ultimate demise.