"Then there's Missy, the hard-working grafter behind the scenes, often overlooked, not always treated the most kindly."
The film is based on the Patricia Grace novel, which caught the eye of the late, pioneering filmmaker Merata Mita.
Gardiner said she felt a strong sense of obligation to help bring the story to the big screen.
"This is a film about whakapapa but it has its own whakapapa which stems back to Patricia's book, which she launched. And at that time Briar and Merata were both part of that book launch."
Gardiner says the production was steeped in ancient Māori practices.
"Tikanga Māori practices have a lot to offer the film industry," she said. "Our film industry is based on an overseas film industry and it's not always relevant to who we are and how we do things.
"For me living in New Zealand in a society where tikanga Māori is so important to so many of us, it just made sense."
The film will show in cinemas across New Zealand this month.
Made with funding from