Peter and Tom set to work learning the skills of the medieval stonemasons to construct a beautiful spiral staircase.

The team defend the castle; Ruth, Tom and Peter explore the art of medieval combat and the building of the castle's defensive structures.

Ruth, Peter and Tom enter the surprisingly colorful world of medieval interior design; Peter and Tom render and limewash the inside walls of a guard tower, transforming its dark stone walls into a bright space.

Construction at Guédelon Castle requires coordination between all the workers.

Peter visits Vezeley Abbey -- from which Richard the Lionheart set off on the Third Crusade -- to examine firsthand some of the influences that shaped the stone architecture of the period.