Lower City, which made its first appearance last year at Cannes in the Un Certain Regard sidebar, is the feature film debut of Brazilian writer-director Sérgio Machado. In terms of content, Machado's story is as old as the hills: Two friends fall in love with the same girl; complications ensue. What makes his film original is its setting and context. Lower City takes place and was shot mostly in Salvador, Brazil, the capital of the north-eastern state of Bahia (the "Cidade Baixa" -- Lower City -- is literally the lower half of the city, separated from the "Cidade Alto" by a vertical distance of nearly 300 feet). The city is built around a natural harbor, and water is ever-present in the film, lending it an often heart-stopping beauty, despite the grinding poverty with which the movie and its story are permeated.

Beneath the blanket of that poverty live Machado's main characters. Deco and Naldinho (played, respectively, by Lázaro Ramos and Wagner Moura) are life-long friends who have rarely been apart. They grew up together, have seen one another through unspecific dark times, and at the moment the film begins, they own a small boat and scratch out a living making short freight runs in and around Salvador's harbor. There's a tremendous, unforced warmth between the two men, possibly aided by the fact that Ramos and Moura are best friends off-screen, as well. Deco and Naldinho call each other "brother," drink together, protect one another, and are close enough to share sexual experiences without tension or awkwardness -- at least at first. They are also from different races (Deco is black, while Naldinho is white), but in the glorious racial patchwork that is Salvador, no one even notices. Almost no one, that is. When an aggressive drunk begins picking on Deco, calling him "nigger" and repeatedly goading him into a fight, it is Naldinho who rushes the stranger and gets stabbed and Deco who attacks the man in search of revenge. His fury at the drunk and abject terror when he seems his friend bleeding says more about the deep love between them than a thousand uses of the word "brother" could. The two would and have done anything for the other; for all intents and purposes, they are one.

When the woman arrives, however, things begin to change. Karinna (an impressive Alice Braga) is a prostitute who needs a change of scenery; in exchange for servicing them both, Deco and Naldinho agree to take her with them on their nighttime freight run across the harbor. At first connected only by sex and convenience, something changes within the trio after Naldinho is stabbed. About to leave the men in favor of quicker, land-bound transportation, Karinna stays to help Deco save his friend. After the immediate panic is over and Naldinho is resting, the tension and emotions of the moment erupt, as they almost always do in Lower City, into an intense, loveless sexual encounter between Karinna and Deco. Inevitably and inexplicably, both men fall in love with the directionless Karinna (that the source of her appeal is never clear is one of the movie's greatest weaknesses). At first, they're able to enjoy drunken flirting and kissing and sharing her attention, but jealousy -- of one another and her tricks, which she cannot afford to up -- quickly emerges, and the love between the two men is severely tested.

It's never clear how much times passes over the course of Lower City, though it's unlikely to be more than a couple of months. During that period, the relationships between Naldinho, Deco, and Karinna flow and evolve, never eclipsing or replacing one another, but also never falling into predictable, manageable patterns. It's to writer-director Machado's great credit that he manages to tell such a cliched story in a determinedly realistic, often unpleasant way. Nothing is easy for his characters, and they rarely make the decisions you ache for them to make -- more often than not, they are ruled by their emotions, and blunder past endless logical solutions to their problems.

The central roles, too, are very well-played. The movie was created primarily through an extensive rehearsal process, during which the trio of actors were coached and coaxed to find their characters within them; whether one buys into this approach or not, the fact remains that there is a tremendous immediacy to all three performances. The early scenes between Deco and Naldinho are wondrous in their easy openness, and all of the moments with Karinna are flecked with swirling, convincing emotions, from desire and hatred to regret and weary hopefulness.

Adding to the intimacy of the story is Machado's commitment to location shooting, and his use of available light and a handheld camera. Because he worked with as small a crew as possible, most of the movie was shot under whatever conditions the team encountered, a situation that results in a camera that feels uncommonly like the eye of a spectator. Because we can see the camera shaking, its observation of the sexual encounters between Karinna and the two men isn't clinical -- instead, the camera-eye seems to be watching curiously, just like we are. Rather than choosing a character on-screen to identify with, we are left with the camera as our representative, peeking into places it shouldn't look, and watching cringingly intimate encounters from which we are unable to turn away. The use of available light, meanwhile, sometimes actually adds lushness to Lower City's already overwhelming visuals. Gorgeous on their own, the blues of the sea, reds of the nightclub's light, and ancient greens of the city walls are bestowed with further depth by conditions that produced film that was slightly under-exposed. When film is "pushed" in development (to compensate for under-exposure), colors look almost engorged with pigment, and this by-product is used to great effect throughout Machado's film. The combination of the story's explosive emotions with its almost too-lovely visuals combine to pack a surprising punch.

When you're under its sway, Lower City is a film with all-encompassing power. Awash in color and passion, it takes control of your senses and leaves you so on edge that your own emotions feel out of control. Once the movie ends, however, and you are freed from its grip, everything fades. In the cold light of day, the characters and their desires seem faintly ludicrous, and you feel a bit ashamed of having been so involved. In many ways, though, our reactions are the same ones the film's characters will have as they get older and further removed from the incidents depicted there in; perhaps our final distance from the film is in fact a sign of its sophistication (or, then again, perhaps it shows a lack thereof).