The new series kicks off with a Grand Design on an epic scale, with the story of one man's heroic attempt to fulfil his childhood dream and bring back from the ruins an incredible castle set in one of the most beautiful landscapes of southern Ireland. Actor Sean Simons fell in love with the ruins of Cloontykilla Castle when he played there as a boy. Years later he bought it, with the idea of turning it into a spectacular, theatrical mock 16th century home, complete with grand baronial hall, luxury bedrooms, sweeping staircases, water spouting gargoyles, Jacuzzis in the battlements and a huge recording studio in the basement. But would it prove to be a magnificent personal masterpiece, or a garish sub-Disneyesque disaster? After borrowing an eye-watering 1.2 million Euros, Sean launches into his project just as Ireland plunges into recession. He has a head full of fairy tales, but no help from an architect, or indeed any formal plans whatsoever. Making things up as you go along is fine if you're building a toy castle, but not when you've got a large team of builders on site, a schedule to hit and the bank looking over your shoulder. Over two years, rooms are built, then knocked down again. Contractors walk out in frustration. Planning permissions are ignored. But somehow Sean's vision starts to come alive... just as Ireland collapses into financial meltdown.

• Kevin McCloud