Eight years before the film's events, Al Bruno Lawrence Shaw, a retired international racing driver, returned home to take over his late father's car-wrecking yard, Smash Palace, on the remote North Island Volcanic Plateau. In the present day, Al's French-born wife Jacqui Anna Maria Monticelli Shaw is increasingly unhappy with his obsession with cars and his refusal to sell the yard, and she fears for the future of their seven-year-old daughter Georgie Greer Robson Shaw. Al spends his days drinking with his policeman friend Ray Keith Aberdein Foley, whose vintage green Ford he is renovating, and mending cars with Tiny Desmond Kelly, an older man who has been his long-time assistant. Yet, beneath his flaws, Al remains a loving and devoted father to Georgie.
Jacqui grows closer to Ray after attending a party with him, seeking his counsel on her deteriorating relationship with Al. When she returns home with Georgie one afternoon, she finds Jacqui and Ray sharing a drink, and Al violently beats and rapes Jacqui. Jacqui leaves Al, taking Georgie with her. She quickly plants herself in a new life as a French teacher and maintains her relationship with Ray, while Al struggles to adapt to the separation and continues to press for access to Georgie.
Al cannot accept the breakup and repeatedly seeks contact with his daughter, prompting Jacqui to seek a protection order after he takes Georgie rabbit-shooting without her knowledge. Tiny offers cautious counsel, sensing that the couple is on a volatile path; he believes Al deserves better, yet he also thinks the restraining order may be excessive and provocative.
Driven by a dangerous mix of pride and longing, Al plans a racing comeback, but Jacqui forbids him from taking Georgie to a race. In a fit of rage, he wrecks part of Jacqui's house with his tow truck and is arrested. With Al showing little effort to contest it, Jacqui's protection order proceeds through the court system.
Al retreats to a hidden hideout deep in the bush, where he kidnaps Georgie from Jacqui at gunpoint. He drives his tow truck off a cliff into a river to create a diversion for the police, launching a widespread manhunt by the Armed Offenders' Squad. The pursuit intensifies as the two settle into their bush refuge, where father and daughter begin to rebuild a fragile bond.
Georgie reminds her father that tomorrow is her birthday, and he tries to mend their relationship by baking her a pie decorated with household candles. After a single night in the hideout, Georgie falls ill, and Al returns to town to rob a pharmacy at gunpoint. He takes the pharmacist hostage and brings her back to Smash Palace, with Georgie in tow.
Ray and Jacqui arrive at the hostage scene inside a large tool shed. Jacqui defies orders and runs through the cordon to be with her husband and daughter, declaring that she still loves Al and proposing they sell the yard and move to Australia. Al agrees to release the pharmacist in exchange for Ray; he forces Ray out to the garage and into Ray's green vintage Ford. Surrounded by police, Al drives Ray through the wrecking yard and onto nearby railway tracks in front of an approaching train in what appears to be a murder–suicide attempt. He maintains he knew the train would switch tracks at the last moment, because he would never destroy a car he loves. The train indeed veers away at the last second, and Al begins to laugh hysterically as the tense standoff ends with the authorities closing in.
