It’s one of the highlights of this year’s Spanish Film Festival. Alberto Rodríguez's Marshland (or La Isla Minima, roughly translated: The Small Island) is a gritty cop drama set against the mesmerising backdrop of rural Spain in the early 80s. It’s a film that makes no obvious pitches to an international audience – it’s not a travelogue, a love story or an easy melodrama. But this is why we have international film festivals. In what other circumstance would this stylish and sinister thriller arrive in our cinemas?

Admittedly, it could be the circumstance of having won 10 (ten!) Goya awards last year—Spain’s highest cinema accolade—including Best Picture, Best Director and Best Actor, elevating it to the Pedro Almodóvar level of awards success... but who’s counting?

The set-up is familiar. Two exiled cops—fresh and idealistic Pedro (Raúl Arévalo) and jaded and corrupt Juan (Javier Gutiérrez)—ride into town unceremoniously on the back of a tractor, and immediately start tracking down a murderer, aided and obstructed by a smattering of misfit locals and suspects.

Pedro and Juan’s backgrounds are paid ambiguous lip service, but actors Arévalo and Gutiérrez are effectively given a pair of blank slates. Both were duly nominated for the Goya for Best Actor, and Gutiérrez won. This approach recurs throughout—there’s a lot we’re not told about character and plot, and Rodríguez carves hidden depths out of what on paper could have been a little flat.

Crime thrillers like this are rarely about the offense itself —they’re exercises in tension and the grim certainties of crime and punishment. Misfit cops arrive in town. People go missing. Corpses are dredged from the Andalusian marshes. Photographs and scorched negatives are passed around, money changes hands, fists are bloodied and crusading cops do their jobs despite institutional corruption and indifference. Plots like this can be airlifted into any context and fitted with different nuance and emphasis, and in this way, the plot of Marshland is no different.

But it’s the context that matters here. It’s a small story on a big, rich stage, right from its opening aerial view of a desolate network of estuaries and swamps, to its perhaps deliberate plot ambiguities. There are two contexts at play here—the political backdrop of Spain's post-Franco period of transition, and the rural depths of Andalusia, Spain’s beautiful southernmost region, here depicted as a forgotten, isolated backwater. It’s where the two of these mesh that the real tension happens. There may be political drama further north, but in Marshland, our cops are confined to a fresh, rural hell.

There are superficial but inescapable similarities to HBO’s True Detective that stretch to a detective framework and a grimy rural backdrop, but they’re just that. The way the trees hang over murky waters, the way suspicion stews in small communities. Perhaps Rodríguez’s greatest achievement here is keeping things so claustrophobic and intimate despite the expansive, often bare landscape. Block out the subtitles and this film is just as rewarding, filled with darkly atmospheric interiors and richly shot, low-angle landscapes. It’s not hard to understand why, at one point when Gutiérrez’s character is knocked unconscious and left by the roadside, he spends some time when he wakes to admire the sunset.