George meets an old friend in Norfolk who sees the potential in the most unpromising of spaces - an old sewage works. With no plans, no budget and just 'brute force and ignorance' - Reuben's audacious idea to create a unique chill out space for his family, including a self-supporting dome roof and a circular carp pond, could be the most incredible Amazing Space ever. George also travels over 5,000 miles exploring Japan. This week features a breathtaking chapel made of intertwining concrete ribbons, where bride and groom tie the knot in the heavens. In the Midlands, a father and daughter work together on salvaging a dilapidated childhood tree house with a budget of just £300. And George and Will continue building a giant toy tree house, and are inspired by a modern tree pavilion. They set about figuring out a way to bring George's impossible childhood fantasy to life using the most unlikely of vegetables.