Two young men fight playfully on a beach surrounded by rocky hills in the opening moments of Karim Aïnouz’s Motel Destino, their tanned bodies glistening under the scorching sun of Brazil’s northeastern coast. Before it’s revealed that the pair are brothers close in age, the scene sets up a torrid queer undercurrent that ripples throughout this erotic thriller even though the three principal characters enmeshed in a dark romantic triangle are all ostensibly straight.

Returning to his home country after last year’s English historical drama Firebrand, Aïnouz takes inspiration from classic noir, notably The Postman Always Rings Twice and Double Indemnity. That sets up expectations for a denouement involving some kind of twist or retribution, which the movie only sort of provides, segueing from violence to a kind of dreamy deliverance. If that ending makes it less satisfying than the sustained tension and intrigue that precede it, there’s still plenty to keep you glued.

At the top of that list are the intoxicating visuals of Hélène Louvart, giving the film palpable heat, physicality and danger that recall the rising-star French cinematographer’s work on Eliza Hittman’s Beach Rats. The striking compositions shot on 16mm have grainy textures pulsing with vitality and electrified by bold splashes of saturated color. The look is like neon even in daylight, adding considerably to the movie’s erotic charge.

The aforementioned beach boys are 21-year-old Heraldo (Iago Xavier) and his slightly older brother Jorge (Renan Capivara), who’s about to have his first child. Heraldo is eager to leave their small beach town in Ceará, move to the city and find work as a mechanic, eventually aiming to run his own garage. But the brothers are on the payroll of local loan shark and drug dealer Bambina (Fabíola Líper), who refuses to let Heraldo go before they do an important two-man job.

That evening at a beach bar, Heraldo hooks up with a stranger (Isabela Catão) and takes her to Motel Destino for a wild night. But once he passes out, she makes off with his money, leaving him locked in the room with no way to pay. Dayana (Nataly Rocha), who runs the seedy roadside joint with her older husband Elias (Fabio Assunção), eventually releases him. But Heraldo makes it to town just in time to see Jorge’s dead body being carted off after his botched attempt to carry out the Bambina job solo.

Aïnouz and screenwriter Wislan Esmeraldo keep the set-up tight, dispensing with unnecessary exposition. The tragedy also serves to fuel Heraldo’s dreams of Jorge, adding the weight of guilt, while fear factors in via his terror of Bambina’s semiautomatic-toting goon Rafael (David Santos) coming after him. Heraldo gets lucky with a hideout when he returns to Motel Destino and Dayana takes him on as a handyman, putting his electrician skills to work.

Production designer Marcos Pedroso renders the sex hotel as a place so sordid you can practically smell it — and that’s even before you see the donkeys humping in the yard. (Nothing like the sight of a whopping mule penis to hammer home a movie’s fascination with lust.) The rooms are bathed in a lurid red glow, as is the central corridor from which staff secure payment through window hatches that allow for the occasional bit of voyeurism. Security cameras also play into that element, uncovering secrets later on.

Perhaps even more pungently descriptive than the look of the place is sound designer Waldir Xavier’s aural racket of moaning and grunting coming from the rooms, sometimes with the added accompaniment of porn channels. Aïnouz doesn’t hold back in his depiction of an environment in which sex and desire are as dirty, sweaty, whiffy and animalistic as it gets. Heraldo even has to remove a large snake that gets into a room, and it’s not one of the sex toys provided by management.

Naturally, Heraldo and Dayana soon start having clandestine trysts while boorish hothead Elias is elsewhere. He’s busy with plans to build an extension and add more rooms, but it doesn’t take him much time to figure out what’s going on. Elias has already threatened to kill Dayana when she tried to run off in the past, so there’s no telling what he’ll do once he discovers he’s being cheated on.

Aïnouz teases out the possible scenarios, stirring in homoerotic tension when Elias starts getting drunk and handsy around Heraldo. It’s clear the older man is no stranger to crime, even before we witness his method of dealing with a motel guest’s inconvenient heart attack. The identity of that guest and his link back to an earlier event is one of the screenplay’s more schematic touches.

Even so, the movie’s overripe sensuality pairs well with the menace of isolated settings like a wind farm on a lonely stretch of beach at night. Likewise the simmering threat of violence or sexual abuse.

But the climactic action is somewhat wayward, with a too easy solution supplied by an unfortunate animal in the wrong place at the wrong time. Dayana talks about being treated like an animal by Elias, and with the donkeys and goat and chickens always around in the motel yard, that metaphor feels heavy-handed. The script’s other failing is its wishy-washy wrap-up of the Bambina business.

Despite its flaws, Motel Destino has mood, rawness and atmosphere to burn, fueled by Amine Bouhafa’s score, which becomes steadily more disquieting as it ratchets up the urgency.

Strong performances by the three leads motor along on the characters’ nervous energy, apprehension or anger, and screen newcomer Xavier keeps you invested in Heraldo’s ordeal. Aïnouz employs the central character as a stand-in for Brazilian youth, whose drive and desire are held back by a corrupt older generation intent on maintaining its power. It’s that kind of oppression that forces young men like Heraldo to bend their fates.