One of the strangest films I have seen in some time, Bruno Dumont’s Slack Bay is – at least on the surface of it – a crime procedural set in the Pas-de-Calais region in the early twentieth century that builds, stylistically and narratively, upon his recent foray into comedy with L’il Quinquin. Unfolding in its entirety against a largely vacant and uninhabited bay, the action moves between three groups of people – the Bruforts, a family of fisherman; the Van Peteghams, a bourgeois family visiting from Tourcoing for the summer; and a pair of policemen who have been assigned to investigate why tourists have started to disappear over the holiday season. Alternating between horror and farce – there’s a cannibalism angle – the film exhibits an uneasy tone that never quite settles into anything stable or recognizable, nor allows the characters to adopt any single acting register for any length of time.

In large part, that’s due to the continually shifting surface of Slack Bay itself – a miasma of sea, sand and soil whose constant winds seem to erode and evacuate everything before your eyes. On top of that, the weather is highly mutable, never quite cloudy and never quite sunny, with different shots in the same scene often appearing to be filmed on completely separate days. As a result, neither the characters nor the audience are ever permitted to get a foothold or stake a claim in any of the film’s spaces, which remain notional and somewhat virtual, even or especially as Dumont devotes most of his energy to elaborating their co-ordinates, with nearly every scene shot outside, on location. Yet that failure to find a footing is what drives most of the action, resulting in a highly plastic, corporeal style that suffuses every surface with a thick viscosity that impedes human movement and momentum.

Of course, it doesn’t hurt that this environment is pretty hard to traverse anyway, with nearly every space – marshland, steep dunes, thick reed beds – seeming as if it has been designed expressly to prohibit human passage. While the Bruforts might subsist on fishing, then, their main holiday industry involves carrying people across the marsh, wading to and fro all day across spaces that are too murky and swampy for even boats to cross. In order to enhance that sense of viscous impediment, Dumont opts for a sound design that continually foregrounds the sound of bodies hitting the ground – bodies being grounded – and bodies trying to move across the ground. At times, it feels as if the microphone is embedded deep in the characters’ muscles as they move from one point to another, not unlike the sensation of hearing the sounds of your own mouth and skull when your ears are blocked.

For that reason, there’s a sense that all the characters are trapped by their bodies as they continually try to move from one space to the next and just as continually fall to earth or find themselves slammed flat by the wind on the few occasions that they find open space. Yet even wide, flat open spaces like the beach feel sludgy and stubborn when confronted with human passage, as evinced in a cumbersome sand-yachting escapade that gets out of hand and plunges one of the main characters into a beached shipwreck. As the sound of wind across water converges with the sound of bodies moving across land, it becomes more and more difficult for the characters to move at all, as they gradually find themselves fixed into awkward and contorted postures that permit only the slightest variations and iterations.

As that might suggest, then, Slack Bay is far more interested in the movement and momentum of its characters than in the crime procedural that unites them, which becomes something of a red herring. In particular, Dumont seems fascinated by the fact that a period drama about the early twentieth century can no longer be grounded or find its footing in the past in any real way, even as he steers clear of revelling in historical simulation or recreation either. Instead, the film occupies a strange, limbic zone that is devoid both of any claim to historical veracity and any self-referential citation of older films – a zone that is perfectly encapsulated in the strange, shifting spaces of the bay itself, which feels more and more like a way of visualizing rather than the preconditions for period drama than the backdrop to an actual period drama.

Against that backdrop, the characters gradually feel undead, like automata or corpses of older period films brought back to life, sometimes stuttering and sticking in the same groove, but always reiterating the mantra “We know what to do, but we do not do.” Amongst them, Juliette Binoche offers the most heightened, artificial and operative performance as one of the the Van Peteghem clan, but Fabrice Luchini and Valeria Bruni Tedeschi aren’t far behind, offering up a stilted and stultifying series of poses that seem designed to punk anyone expecting a feel-good French period drama. If anything, these characters are most alive when they’re being consumed by the cannibals – at least then they seem to have some kind of vitality, if only because they contribute vicariously to the vitality of the cannibals themselves, who don’t seem to suffer from quite the same degree of putrid decay.

As that unfolds, Dumont continues to obsessively map the vast co-ordinates of the bay – the marsh, the dunes, the harbor, the hillocks – and yet this only serves to jettison it further from any lived or embodied sense of space. As the policemen quickly discover, the only clear vantage point of this vista is the Van Peteghem villa, which functions as the anchor for most of Dumont’s establishing shots. Yet the sheer architectural incongruity of this villa – an Egyptian temple in the Ptolemaic style – displaces and decentres it in turn from all the vistas and vantage points that it generates, producing a strange, lateral sense of space that always seems to be purely notional or utterly oblique to the characters actually occupying it. On the one hand, that constrains the characters even more, but it also provides them with a strange sense of mutability as well, the feeling that they are capable of changing and decaying in ways that lie outside the historical scope and narrative set out for them.

In other words, Dumont resurrects a series of historical zombies but then turns them loose to act in increasingly bizarre, anarchic and anachronistic ways, with gender, in particular, becoming so fluid that characters seem able to choose their sex and sexual orientation at will. As the film draws towards its close, that offsets the sludgy substrate with an almost equally oppressive buoyancy, in which the prospect of floating off into the sky becomes the only alternative to trudging thanklessly across the land. It’s a beautiful image of the dilemma facing historical cinema – slavish recreation to the historical ground or vertiginous disregard for it – and not unlike the kinds of radical revisionism that Dumont has refined in his career from Flanders onwards. Yet even within his filmography there’s a stubbornness and an awkwardness to Slack Bay that remains unique, a kind of idiot savant sensibility that refuses to understand how to tastefully and tactfully tell historical fiction in the twenty-first century.