The Roman legionary fort of Caerleon in South Wales is one of the most famous and best preserved Roman sites in Britain. It stood on the edge of the Roman Empire, but its huge amphitheatre and immense baths, and the scale of its ruined walls, are all testament to its power and importance. But just outside the fort, archaeologists have discovered signs of yet another huge structure leading from the fort down to the river. It seems to be a vast courtyard surrounded by stone buildings and with a mysterious square structure standing in the centre. Joining a large team from Cardiff University, Tony and the Team have just three days to help piece together the answer. And when they do, it casts new light on what was once seen as solely a military outpost.