Laurence Llewelyn-Bowen visits some of the finest houses in Wales, stepping back in time to uncover their hidden stories. He turns his attention to Glynllifon - a huge neo-classical mansion near Caernarfon in Gwynedd. Laurence discovers that the vast estate was once home to one of the country's most powerful, and colourful, aristocratic families. He meets the young couple who are battling to restore this crumbling Goliath to its former regal glory.