In the Northland town of Kaitaia in spring 1978, nineteen-year-old Gerry Austin (Kelly Johnson) (a.k.a. 'Blondini') steals a wallet and uses the cash and a driver’s license to rent a bright yellow Mini, starting a loose, aimless drift down to Auckland. There, the middle-aged John (Tony Barry) struggles to convince Sue (Shirley Gruar), his girlfriend of six years, to stay with him. After a night of drinking, John decides to travel to Sue’s sister’s home in Invercargill to win her back, a move that sets the other two on a shared, reckless path. While searching for transport, John saves Gerry from receiving a ticket for failing to wear a seat belt, and in return Gerry offers John a lift for part of the way, sparking an uneasy alliance between two men from very different worlds.
The trio’s road trip kicks off with a dash of bad luck and bad choices: they stop for petrol in northern Waikato but drive off without paying, pulling police attention onto the mysterious yellow car, a moment that deepens their bond even as it tightens the net around them. Soon after, Gerry and John pick up Shirl (Claire Oberman), another drifter headed toward Wanganui. Shirl reveals she is a virgin, and Gerry quietly bets that this status will change before they reach their destination. In a display of improvisation born of desperation, they also steal petrol during a stint in central North Island, and a motorcycle officer gives chase. The trio eludes arrest by slipping into a car wrecker, an improvised sanctuary that keeps them on the move.
After Shirl leaves, Gerry and John press on to Wellington, where they reconnect with Mulvaney (Bruno Lawrence), an old associate of John’s. Mulvaney supplies money and drugs in exchange for parts of the Mini, and Gerry ends up reuniting with Shirl at Mulvaney’s garage. The next morning they set off for the Interislander ferry, but Gerry blasts through a red light and a police pursuit zips through central Wellington. They narrowly escape by driving through Wellington’s railway station and stowing the Mini in an empty boxcar that’s being shunted onto the ferry.
In Picton on the South Island, the boxcar is attached to a train bound for Christchurch. Gerry, John, and Shirl ride it south, decorating the interior with Gerry’s nickname “Blondini” and odds-and-ends found in other wagons. After a night of partying, Gerry’s victory in his bet with Shirl comes and goes, and the trio discovers the wagon will not depart for the West Coast until that night. They pass the day in Christchurch, only to learn that Shirl has been arrested for shoplifting and that a national manhunt has been launched for the “Blondini Gang.” The Mini is pursued along the Lake Hāwea shoreline by a determined officer who almost catches Gerry and John before veering off to avoid a combine harvester. Gerry stops to check the officer is all right and even mocks the car’s radio, a moment that highlights the pair’s defiant swagger.
Further south, they sell more parts from the car at Cromwell. In Dunedin, they meet Snout (John Bach), an eccentric ally who helps them dodge a police roadblock and offers to buy Gerry’s set of flags gathered for the Mini’s antenna. Gerry hesitates at first, superstitious that the flags have kept them safe, but he relents under John’s urging. After leaving Snout, police are tipped off about their route toward Invercargill.
In McNab, John is spotted by officers and drives off in the Mini, not realizing Gerry is lying under the car. Gerry is arrested, but escapes from the police car and climbs atop the fleeing Mini. The pursuit culminates with a PIT maneuver that hurls Gerry from the vehicle; he is struck by a pursuing police car, and John says farewell to the injured partner, then takes the Mini and presses on toward Invercargill. A trucker at the scene refuses to move aside for the police out of respect for Gerry, leaving his ultimate fate unresolved in the moment.
When Invercargill finally arrives, John is greeted by a crowd of admirers who have tracked the Blondini Gang’s cross-country journey. Members of the Armed Offenders Squad appear and shoot a hole in John’s petrol can. Exploiting the distraction, John drives through a cemetery and makes it to Sue’s house just as the leaking petrol ignites, triggering an explosion that destroys the Mini. He reunites with Sue, and the two share a charged moment as police surround the house. With the situation at its peak, John bids farewell to the supporters, cracking jokes for the onlookers as police take him away, leaving the fates of Gerry and the larger story hanging in the balance.
