A self-obsessed young man makes his way to the party-to-end-all-parties on the last day on Earth, but ends up saving the life of a little girl searching for her father. Their relationship ultimately leads him on the path to redemption.
The film takes place in Perth, and begins ten minutes after an asteroid has collided with earth in the North Atlantic, leaving approximately twelve hours until the subsequent global firestorm reaches Western Australia. James and his lover, Zoe, are having sex for the last time at her beach house, where she reveals that she’s pregnant with James’ child. Wishing to block out all feelings and avoid what’s coming, James berates Zoe for sharing her news and leaves for “the party to end all parties”.
After having his car stolen, he comes across two men who have kidnapped a young girl and are planning to rape her. James kills them, and rescues the girl. The girl, named Rose, explains that she was separated from her father in Malaga en route to her aunt’s house in Roleystone. Without enough petrol, and wishing to get to his party, James instead plans to leave her with his sister and her children. But upon arriving, he finds his sister and her husband dead in the shower, and three crosses marking what appears to be his nieces’ graves, in what is an apparent murder suicide.
Other attempts at locating Rose’s dad, or someone to leave her with, have sobering results, and James eventually heads to the party with Rose in tow. The party is overflowing with people, a game of Russian roulette is being played, and an orgy is going on inside the house. James is noticeably uncomfortable and appears to want to leave. James meets with the host of the party, Freddy, whose sister is James’ girlfriend, Vicki. James leaves Rose in the pool to speak with Vicki. In a reversal of the earlier scene with Zoe, James attempts to share a serious moment with Vicki, only for her to berate him for bringing her down with his news.
Vicki shows James a bunker built underneath Freddy’s garage, which obviously does not have sufficient food, protection, or space for the miraculous survival Vicki envisions. James tells Vicki and Freddy that they’ll all die, even with the bunker. Freddy’s reaction to this statement informs Vicki that her brother had known this all along. James accepts that his death is inevitable and can’t be blocked out, and commits himself to reuniting Rose with her family.
Meanwhile, outside, a drug-affected woman follows Rose, claiming that she is her daughter, Mandy. When James finally comes back outside to find Rose, she is hallucinating and vomiting after being coerced into taking ecstasy pill, with the woman leaning over her. James tries to leave the party with Rose, causing the woman to scream that he is kidnapping her child. Freddy holds James at gunpoint, before Vicki calmly takes the gun and shoots the woman, telling James to go.
James drives Rose to his estranged mother’s house, with whom he reconciles whilst Rose recovers. She gives James petrol and Rose some old clothes, and the pair leave for Rose’s aunt’s house. Upon arrival, nobody seems to be home, but James finds the bodies of Rose’s family, including her father, outside in what seems to be a mass suicide. Although hysterical at the news of her father’s death, Rose insists on seeing him. James comforts her and brings her his body, and they lay him by a pond with flowers as she tells him that her dad wanted them to be together for the end. James then confides in Rose about his relationship with Zoe and her pregnancy, which leads him to realise his love for her. Rose convinces him to make amends with her while he still can. He heeds her advice, and the two share an emotional farewell before James leaves. His car overheats on the highway as the firestorm approaches, and he runs for the rest of the way. He finds Zoe on the beach, watching the approaching firestorm. She is initially hostile towards James, however the two quickly reconcile and confess their mutual love. The pair then embrace, and turn towards the ocean as they are consumed by the firestorm.