Historian Ruth Goodman and archaeologists Peter Ginn and Tom Pinfold turn the clock back to learn the skills of the medieval castle builders - by joining the largest archaeological experiment in the world. Although Britain has some of the finest remaining castles of the medieval period, many of their secrets have been lost in time. So Ruth, Peter and Tom travel to Guedelon, in the Burgundy region of France, where an ambitious, 25 year project is under way to build a medieval castle from scratch, using only the materials and tools available in the 13th century. As our trio get to grips with the skills and crafts of medieval construction, they recapture an era, and a camaraderie not often seen today in the workplace. For six months they experience the daily rigours of life in the 13th century, from how to dress to the art of combat. 'Secrets of the Castle' brings medieval history to life in a fun and informative way.