Architect Chris Moller meets Southland farmer Lachlan McDonald, who's building a modernist concrete home with a controversial roof in one of the most remote parts of NZ. Deer farmer and bachelor Lachlan McDonald is building a three-bedroom concrete home in the hopes to fill it with a family in the future. However, the choice of location is one of the most remote and stormy parts of the country - The Catlins. He's hired a top Auckland architect who is scratching his head at Lachlan's decision to project manage his first build himself. His choice of builder is also a good mate who specialises in constructing local milking sheds. Will this Grand Design be a perfect fusion of passions and experience or are these personalities destined to clash?

Chris meets Gus and Sarah whose solution to spiraling house prices is to make their first home an Earthship - an off-the-grid house made of recycled rubbish, earthen bricks and clay. An Earthship is a non-traditional home built using recycled materials such as bottles and tyres, and even mussel shells for insulation. Young Coromandel couple Gus and Sarah Anning decided to step outside the norm with their Grand Design when they realized they couldn't afford a traditional home. Enlisting the help of community volunteers, both here and overseas and using unique building techniques originally designed for the desert in California, it's not certain how this Grand Design will fare in Coromandel's temperamental climate.

Chris meets Scottish migrant and urbanite, Scott Lawrie, who has a dream for a new life and a radical new stainless steel home in the remote hills behind Pakiri. Sydney-based writer Scott Lawrie's plans for his new life in New Zealand are encapsulated in a sculptural steel house he is building on a remote rural hillside behind Pakiri beach. Scott has an unrelenting refusal to compromise on his "legacy", but a budget can only be stretched so far. Will Scott realize his extraordinary dream?

Chris meets builder Steve Sygrove, who's planning to build and ornate and colourful American Gothic home in the Titirangi bush. Fifth generation builder Steve Sygrove and his wife, Chrissy, have a passion for things pretty, floral and pink. Their unique build in the Titirangi bush near Auckland is a handcrafted American Gothic style house complete with ornate detailing like a Juliette balcony, spandrels, a horseshow window, lacework valences, and interior walls made of fabric. Steve rallies against the bureaucracy that is stifling the creativity in his craft and expects this grand dame of a building will be his swansong.

Chris meets architect Nic Ballara, who's planning to build a house on a steep 45-degree slope overlooking Wellington. Nic Ballara clearly has a head for heights as he starts to build a family home for him and his wife Callie and their 12-year-old daughter. Nic's site in the earthquake prone city of Wellington is so steep that it looks virtually impossible to build on, however Nic is convinced he has a solution and is determined to build his first home there. A logistical nightmare lies ahead as this Grand Design looks to be an uphill battle throughout.

Chris meets Hamish and Diane Divett, who are rebuilding their house on the most unlikely spot - on the edge of a crumbling cliff top that plummets 40 metres to the sea below. Surfing Pastor Hamish Divett and his psychologist wife Diane have lived by the ocean for years, but in a dark, south-facing house that failed to take full advantage of the beautiful vista. To get the view they desperately desire, the couple have decided to push structural and logical planning to the limits. By building on a crumbling cliff with a sheer drop to the sea below, the Divetts will push their team to the edge to see this Grand Design though to completion.

After years of living apart with their separate children, Mike and Catherine are finally building an extraordinary straw bale together on top of a rocky outcrop in central Otego. Between them, Mike and Cathy have seven children from their previous marriages. With the last child finally moved out of home, the couple are going to build a Grand Design in which they will live alone together for the first time. They will be calling on Catherine's skills as one of the few female joiners in the country and Mike's talents as an inventor to build a unique straw bale and hemp house on an exposed rocky outcrop near Wanaka.

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?