Beth left her small town and, despite her parents' disapproval, married Jake "the Muss" Heke. After 18 years they live in an unkempt state house in an unnamed New Zealand city and have five children. Their interpretations of life and being Māori are tested. Their eldest daughter, Grace, keeps a journal in which she chronicles events as well as stories she tells her younger siblings.
Jake is fired from his job and is satisfied with receiving unemployment benefit, spending most days getting drunk at the local pub with his friends, singing songs, and savagely beating any patron he considers to have stepped out of line. He often invites crowds of friends from the bar to his home for drunken parties. When his wife "gets lippy" at one of his parties, he brutally attacks her in front of their friends. Beth turns to drink when things go wrong, and has angry outbursts and occasional violence of her own, on a much smaller scale. Her children fend for themselves, resignedly cleaning the blood-streaked house after their father has beat their mother.
Nig, the Hekes' eldest son, moves out to join a gang whose rituals include getting facial tattoos (in Māori culture called tā moko). He is subjected to an initiation beating by the gang members but is then embraced as a new brother, and he later sports the gang's tattoos. Nig cares about his siblings but despises his father. He is angered when his mother is beaten but deals with it by walking away.
The second son, Mark "Boogie" Heke, has a history of minor criminal offences; he is taken from his family and placed in a foster home as a ward of the state due to his parents' home life. Despite his initial anger, Boogie finds a new niche for himself, as the foster home's manager Mr. Bennett helps him embrace his Māori heritage. Jake does not care that Boogie was taken away; he comments that it will do him some good, toughen him up a bit. Beth is heartbroken and scrapes money together to visit him. Jake pays for the rental car from gambling winnings but deserts the family to go to the pub, and they never make the journey.
Grace, the Hekes' 13-year-old daughter, loves writing stories. Her best friend is a homeless boy named Toot, who lives in a wrecked car. She despises the future she believes is inevitable and is constantly reminded of getting married and playing the role of a wife, which she believes comprises catering to one's husband's demands and taking beatings. She dreams of leaving, and being independent and single.
Grace is raped in her bed by her father's friend "Uncle Bully", who tells her it is her fault for "turning him on" by wearing her "skimpy little nighty". She becomes depressed and seeks support from her friend Toot, with whom she smokes marijuana for the first time. Toot kisses her, but she reacts violently and storms out, believing he is "just like the rest of them". After wandering through the city streets, Grace comes home to an angry Jake with his friends. Bully asks for a goodnight kiss in front of everyone, to test his power over her. Grace refuses, and her father tears her journal in two and nearly beats her up. She runs out to the backyard crying. Beth returns home from searching for Grace, only to find that she has hanged herself from a tree branch in the backyard.
Jake stays in the pub with his mates, while the rest of the family takes Grace's body to a tangihanga. Beth stands up to him properly for the first time as he refuses to let her be taken to the marae. The film cuts back and forth between the mourning, Jake in the pub bottling it up, and the family on the marae. Boogie impresses Beth with his Māori singing at the funeral, and Toot says his goodbyes, telling Grace the gentle kiss was all his gesture meant. Boogie reassures Toot that Grace loved him, and Beth invites Toot to live with them.
Reading Grace's diary later that day, Beth finds out about the rape and confronts Bully in the pub. Jake at first threatens Beth, but Nig steps between them, protecting his mother. He hands his father Grace's diary, and Jake reacts by severely beating Bully and stabbing him in the crotch with a glass bottle. Beth blames Jake just as much as Bully, so she leaves and states her intention to take their children back to her Māori village and traditions, defiantly telling Jake that her Māori heritage gives her the strength to resist his control over her. Jake hopelessly sits on a curb outside the pub as the family leaves, with sirens wailing in the background.Rena Owen as Beth Heke
Temuera Morrison as Jake "the Muss" Heke
Julian Arahanga as Nig Heke
Mamaengaroa Kerr-Bell as Grace Heke
Taungaroa Emile as Boogie Heke
Rachael Morris Jr. as Polly Heke
Joseph Kairau as Huata Heke
George Henare as Mr. Bennett
Cliff Curtis as Uncle Bully
Pete Smith as Dooley
Calvin Tuteao as Taka
Shannon Williams as Toot
Mere Boynton as Mavis
Once Were Warriors is the first feature film produced by Communicado Productions. The production won Best Film at the Durban International Film Festival, Montreal Film Festival, New Zealand Film & Television Awards, and Rotterdam Film Festival. It also became at the time the highest-grossing film in New Zealand, surpassing The Piano (1993). Once Were Warriors was nominated for the Grand Prix of the Belgian Syndicate of Cinema Critics.
The film was shot at a local state house, located at 33 O'Connor Street, Otara, in the Auckland metropolitan area. The neighbours of the house used for filming complained on numerous occasions due to the film's late night party scenes.
Once Were Warriors was critically lauded on release, and the film currently has a rating of 93% on Rotten Tomatoes based on 44 reviews with an average rating of 7.8 out of 10.
Roger Ebert gave the film three and a half stars out of four and observed: "Once Were Warriors has been praised as an attack on domestic violence and abuse. So it is. But I am not sure anyone needs to see this film to discover that such brutality is bad. We know that. I value it for two other reasons: its perception in showing the way alcohol triggers sudden personality shifts, and its power in presenting two great performances by Morrison and Owen. You don't often see acting like this in the movies. They bring the Academy Awards into perspective."
The film has also been criticised for contributing to or in some cases creating negative stereotypes about Māori. Ferguson writes that "This movie was very influential in the labelling of Māori as violent individuals, who indulged in alcohol and wife-bashing on a weekly basis...Internationally we have had to work hard to dispel the myths that arose from this movie, mainly to prove to the world that not all Māori are like those portrayed in the movie." At the same time, Ferguson emphasises that the film addresses domestic abuse, a problem that, due to colonisation and inequalities, disproportionally affects Māori communities.
A 2014 New Zealand survey voted Once Were Warriors the best New Zealand film of all time.A sequel to the book, What Becomes of the Broken Hearted? (1996), was made into a film in 1999. However, that sequel film was poorly received compared to the original.
The third book in the trilogy, Jake's Long Shadow (2002), has not been made into a movie.
Once Were the Cast of Warriors (2014) is a documentary film made for the 20th anniversary of the original release of Once Were Warriors.