Even by the usual standard of apocalyptic thrillers, Zak Hilditch’s fourth feature These Final Hours is remarkably bleak. How would you spend your last twelve hours on earth, it asks, and who with, and doing what? The answers provided by morally ambiguous central character James (Nathan Phillips) are perhaps the ones we’d hope we’d provide for ourselves, but the film forces you to think the unthinkable and consider just how the shock of an end to it all would affect your thinking.

It starts as it means to go on – the first thing we hear is the chilling wail of a siren echoing through the streets of Perth in Western Australia. The streets are in chaos, people attacking and killing each other indiscriminately, having orgies or just trying to flee. The cause of it all is the news that an asteroid has hit the earth in the North Atlantic, creating a vast wall of fire that is spreading around the world and which will reach Perth in just twelve hours. James is at a beach house with his lover Zoe (Jessica De Gouw) who reveals that she’s pregnant. James, not wanting to have to deal with what’s about to come, opts to abandon her and find his other girlfriend, Vicki (Kathryn Beck) who is at “the party to end all parties” being thrown by her brother Freddy (Daniel Henshall). En route, he rescues a young girl, Rose (Angourie Rice), from a pair of men planning to rape her. He refuses to take her to her aunt’s house in Roleystone but instead offers to leave her with his sister and her family. But his sister and her family are dead in a murder-suicide pact and James is stuck with Rose, taking her to the party where Vicki shows him the pathetic fall-out shelter built by Freddy that won’t save anyone. Appalled by the hedonism of the party and finally coming to terms with the inevitability of his impending death, James takes Rose to her aunt’s only to find that her father and the rest of the family have taken the same decision as his sister. Rose wants to stay with her dead family and face the end with them, persuading James that he should really be with Zoe. But is there still time left for him to find her before the wall of flames obliterates all life of the planet?

When we first meet him, James is a coked-up, self-absorbed arsehole, abandoning one pregnant lover to spend the final hours partying with another. The story is as much the tale of his redemption as it is a tale of Armageddon. It’s a very different film to his previous features, the drama Plum Role (2007) and comedies The Actress (2005) and The Toll (2010). It’s the ultimate road trip to hell as society collapses with depressing speed and human behaviour degenerates into primitive, Neanderthal chaos. And given the behaviour of some of the people James and Rose meet on their journey, you have to winder if, even it was possible, would the world be saving.

But it wouldn’t be possible – no-one’s coming to save us this time. There are no superheroes waiting in the wings, no last-minute heroic missions into space to save the human race, no intervention from a higher being. This is a film in the same vein as Testament (1983), Threads (1984), or Melancholia (2011), films in which despair is the key note and Hollywood endings are not required. The end is coming no matter what James does – all that matters is how he spends the hours he has left.

There’s also an element of Apocalypse Now (1979) about Jason’s journey which takes him into a hedonistic heart of darkness. There are also affinities to Stanley Kramer’s equally harrowing On the Beach (1959) which also featured Australia as the last place left on Earth with the effects of the apocalypse racing towards the survivors with terrible certainty.

The progress of the wall of flame is subtly indicated throughout the film, verbally by a radio DJ (David Field), who we realise late in the film has stopped broadcasting, reeling off the places that have already succumbed and even more subtly by the sky gradually becoming more sickly as the story goes along. There are moments of irony (James and Rose drive past a road sign for a housing development reading “the future of living”) and moments that are genuinely heart-breaking (James finding his sister and her family dead in their home, a scene in a library with a father facing the most heart-wrenching of decisions, the affecting moments where James and Rose try to keep each other in sight as long as they can as they finally separate). The last twenty minutes in particular are one emotional gut punch after another.

None of this would matter much if the two lead performances weren’t up to scratch but both Phillips and Rice are fantastic, he managing the transition from hateful slacker to man who realises the terrible mistake he’s made just in time really rather well, she tugging at the heartstrings without even being annoyingly precocious. Rice had featured in Transmission (2012) which feels like a dry run for These Final Hours – Rice plays another child in an apocalyptic Australia (it’s a deadly virus at the heart of this one) travelling with her father who has to learn new skills and harsh life lessons if they’re both to survive (a small amount of footage from the short turns up in the opening minutes of These Final Hours).

These Final Hours was one of a small group of smaller scale apocalyptic films that appeared around the same time – Lars Van Triers’ aforementioned Melancholia, 4:44 Last Day on Earth (2011), It’s a Disaster (2012) and Goodbye World (2013) among them, all preceded by Last Night (1998). These Final Hours is one of the best of the bunch, a brilliant, relentlessly bleak, beautifully acted and most importantly moving tale of doing the right thing when there’s no future left. “It’s beautiful,” gasps Zoe as the wall of flame finally reaches her at the climax. And in an odd sort of way, she’s absolutely right.