Water, wine, and blood—the characters in Argentine writer-director Lucrecia Martel’s La Ciénaga (“The Swamp”) exist in a sort of a Roman Catholic soup. This insinuating debut feature ends with a more definitive event than Martel’s more recent The Holy Girl, but is otherwise scarcely plotted. During a sultry summer, a gaggle of barely supervised siblings and cousins hang out by the fetid pool, tramp in the woods, and watch TV reports about a local sighting of the Virgin Mary. This is the humid provincial life of Martel’s childhood, rendered with dispassion and deadpan poetry. Although the central family is experiencing Faulkneresque rot, little drama results. Instead, the film is propelled by fluid framing and editing, as well as a series of motifs: A cow slowly perishes in a bog, mom offers cool drinks, and people keep falling down. Call the last symbolism, yet Martel keeps the tone matter-of-fact. The film screens at 8:30 p.m. (see Showtimes for other dates) at the American Film Institute’s Silver Theatre and Cultural Center, 8633 Colesville Road, Silver Spring. $8.50. (301) 495-6700.