The series finale sees Marty import two old American barns from New York valley, which are raised by heritage builders and merged with a design for a modern home. Timber merchant Marty Verry and his Venezuelan wife Morella have imported two historic New York barn frames that could be considered the oldest buildings in New Zealand. With plans to assemble the barn on the couples' rural site on the outskirts of Auckland, they intend them to become part of a modernist mansion acting as a tribute to the different timber Marty loves. But will the new homes honour the history they are built on or is this Grand Design set to take on a life of its own?