MIAMI - One of the pleasures of smaller film festivals, where one's viewing is less dutifully structured around competitions and mandatory big-name premieres, is pick-and-mix scheduling -- selecting the day's viewing on a mixture of gut instinct and chance convenience, and seeing what unexpected patterns and conflicts emerge.

Coincidentally enough, I wound up seeing two Brazilian films back to back yesterday -- not such an improbable occurrence in a festival programme that accommodates Latin-American markets so generously, but their wildly contrasting impressions of urban social malaise and personal distrust proved mutually enhancing. Mexico and Germany were selected by the Miami programmers for dedicated showcases this year; on yesterday's evidence, however, Brazilian film is fighting fit.

There's a fierce, Pablo Trapero-like sense of purpose to "A Wolf at the Door," a jumpy, pile-driving directorial debut for Fernando Coimbra that seems a gateway to more illustrious things -- as plausibly within the mainstream as the arthouse genre pocket. For now, however, this genuinely alarming child-abduction thriller is impressive enough in the present tense: understandable comparisons were drawn to Denis Villeneuve's "Prisoners" when both films premiered on the fall festival circuit, but Coimbra's style is as hot and restless as Villeneuve's is clammily, effectively oppressive. Flashbacks are frequent and fussily layered in what only gradually emerges as a familiar other-woman story with a particularly severe outcome; it's the palpably humid atmospherics that make this more than a sliced-up procedural.

Well, those and an fervid, last-nerve performance from Leandra Leal as Rosa, the young, impulsive mistress of married brute Bernardo (Milhem Cortaz), a man whose hold over not one but two women remains the film's most gapingly unsolved mystery.  When Bernardo's six-year-old daughter goes missing, collected from school by an apparently familiar woman, Rosa becomes the prime suspect -- it's not long before she rather unconvincingly admits that she was kidnapper, but only under someone else's instructions.

With those fundamentals established in the opening act, Coimbra goes into the considerably more conflicted whys of the event -- and the lingering question mark of where the girl has been taken. The script deals out these revelations in intricate, one-step-forward-two-steps-back fashion, the staggered chronology making queasy sense of Rosa's motives, even as the depth of her derangement surprises.

Daringly -- and only arguably intentionally -- the film's sympathies seem to rest largely with Rosa, if only because her character is so much more contoured and immediate than those of her victims. Bernardo's wife Silvia (Fabiula Nascimento) is depicted as an ineffective, even neglectful, maternal figure; given the violent abandon with which her husband abuses Rosa, perhaps she's been pummelled into blankness. "A Wolf at the Door" bristles with indignation over the paternalism of familial and administrative structures of Catholic Brazil -- late in the film, a crucial violation of Rosa's bodily rights is as gaspingly horrific as any scene of onscreen brutality in recent memory, and the fallout only gets more desperate from there.

Guided by the formidable cinematographer Lula Carvalho ("Elite Squad," "RoboCop"), the camera becomes more vertiginously mobile as the resolution becomes more claustrophobically hopeless, stranding characters in mirrored reflections and withholding perspective to jolting effect -- there's a risk here of formally overstructuring this fact-based story to the point of gimmickry, but the closing coda is as dully sobering as the build-up is sensational. Some will take Coimbras to task for exploiting a tragedy, but there's little denying that he's made a living, breathing film of one.

The angry urgency of "A Wolf at the Door" could hardly be more directly countered by the coolly temperate intrigue of "The Man of the Crowd," a measured, meditative, slightly muffled adaptation of the 1840 Edgar Allan Poe story of the same title -- relocated to contemporary Belo Horizonte shorn of its Gothic tension, but with its mordant views of human loneliness largely intact. In Poe's story, a narrator tracks a sinister stranger overnight through snaking London streets; Marcelo Gomes and Cae Guimaraes' update finds alternative manifestations of this monomania, stretching to similarly obsessive internet stalking. Isolation-induced insanity, it seems, never goes out of style. 

Poe's nameless, blank-slate protagonist here takes the equivalently opaque form of Juvenal (Paolo Andre), a painfully shy train driver who glassily observes passengers and passers-by  with no hint of comprehension or empathy. In the film's most significant departure from Poe's text, his interest is tentatively sparked by the arrival of colleague Margo (Silvia Lourenço, a gawkily appealing foil to Andre's whispery stillness), a sweet, superficially outgoing woman effortfully staving off her own social inadequacies with online activity. Engaged to man we rather pointedly never see, she invites a reluctant Juvenal to be the witness at her wedding -- a somewhat telling request, given the stateless vacuum in which the film appears to take place.

Gomes and Guimaraes' lateral interpretation of the source material is only intermittently rewarding -- missing from this more sentimental arrangement of Poe's themes is a ratcheting sense of peril or uncertainty. (Perhaps that's deliberate; these 21st-century drifters have become divorced even from fearful human curiosity.)

As a sensual evocation of solitude and disconnection, however, the film succeeds rather stunningly. Cinematographer Ivo Lopes Araujo's imagery has an alienatingly chalky, constructed quality, but it's the unorthodox decision to shoot in a square aspect ratio that is most bluntly effective, creating something tantamount to cinematic tunnel vision -- Juvenal's world could hardly be made smaller. I kept expecting "The Man of the Crowd" to open up, visually and otherwise; that this silently soulful film resolutely refuses to do so seems a thematically necessary frustration.