A father and son wander into a rave in the middle of the desert. They're looking for a missing child, a daughter and sister, who disappeared a year earlier. Her tracks have vanished, but they might have come through here.

The duo meets with a group of homeless partiers, who suspect the missing girl may have gone to their next destination. Another mythic rave even further in the wilderness. With no options left, the father and son pack their bags and follow this oddball family into the unknown.

That's all you should know of Sirat, the masterful and mystical thriller from Oliver Laxe that defies convention and easy categorization. It's part Mad Max, part Gaspar Noe, part mythic apocalyptic western. Whatever the ingredients, the finished product is an indescribable masterpiece that will haunt me for a long time.

Laxe spends the first half hour building his world. We catches glimpses of potential threads a more traditional narrative would pursue. There's a missing girl, a looming threat of war, a world losing its resources, and an inherent distrust between generations and classes. Yet what it pursues, or doesn't pursue, is nowhere near as simple as you'd think.

Instead, Sirat is a moody, unknowing exploration of what happens when you gradually lose everything to the point that only survival matters. Laxe uses his sparse environments to great effect. Minimalist turns maximalist as the vast emptiness swallows us whole. The hypnotizing soundtrack becomes all-encompassing. We can only see the road ahead, even where are no tracks to follow.

None of this would work without a talented cast, and Sirat delivers here in spades. Sergi Lopez is fantastic as the well-intentioned but hopelessly lost father, while Jade Oukid and Stefania Gadda provide the heart of the film as two parts of the found family unit with different outlooks on life.

Laxe, a talented filmmaker whose previous work Fire Will Come already signaled the arrival of a major talent, rises to a whole new level of his craft. His vision is bursting with tone and mood, yet he never sacrifices subtext for visuals. Instead, everything serves a final gut-punch message that recontextualizes the film entire.

In one bravura sequence, Laxe puts the audience through such an ordeal that, when it was finally over, the opening night crowd burst into spontaneous applause. There was an aura of relief that washed over us in unison. It's the work of a young master toying with his audience like a cat with its prey.

Sirat is a triumph. It is at once a nuanced exploration of sorrow and grief, a bleak adventure story, an apocalyptic nightmare, a warning of what is to come, and more. It never over-explains itself nor does it overstay its welcome. We learn enough to go along for the ride, and can leave only when Laxe allows us to.

It is, to date, the best film of the festival and one of the best films of the year.