There's been some studiously arty, wannabe-Euro cinema coming out of Latin America recently, so The Maid comes as a pleasant surprise. A sharp, acidly funny black comedy from Chile, Sebastián Silva's movie is about Raquel, a live-in housekeeper for a Santiago family who becomes a raging passive-aggressive sociopath when her employers bring in extra help. With her troll-like physique, lipless grimace, and frumpy curls, Catalina Saavedra's ferociously territorial cleaning lady is an indelible creation—pathetic and vindictive, but never entirely ridiculous. The upper-class family that single, childless Raquel works for—frazzled parents and teasingly entitled children roaming about their spacious, tasteful house—is the only structure she has ever known; we understand why she unravels when her role is threatened, even as we giggle at what a psycho she becomes.

Silva shot The Maid in his parents' home, and the precision of autobiography is felt in the uneasy push-and-pull of affection, intimacy, resentment, and guilt that colors the upstairs-downstairs relations on-screen. What might have been a condescending social-issue drama about oppressed servants or a shrill send-up of the ruling class instead becomes a carefully etched character study that navigates an impressive series of tonal shifts. Starting out as a handheld-driven observation piece, The Maid gradually takes on farcical and thrillerlike rhythms as Raquel methodically sabotages her new assistants. We expect her to go apeshit and bash everyone's heads in with her vacuum or poison them with bleach. But Silva has something else up his sleeve: In the film's final act, a disarmingly smiley, effortlessly modern housekeeper shows up with her iPod and jogging clothes, and the story gravitates toward awkward and revealing new emotions. The film—like its intriguing weirdo of a heroine—is, up until then, so tightly controlled that it's a relief when it discovers how to let go.