Writer-director Georgina Garcia Riedel’s feature debut is so good for so long that it breaks the heart to watch the film lose its way. Opening with silent, static shots of the characters’ sleepy Arizona community, How the Garcia Girls Spent Their Summer orients you to the marginal lives of three generations of single Garcia women — widowed grandmother Doña (Lucy Gallardo), divorced mother Lolita (Elizabeth Peña), and virgin daughter Blanca (America Ferrera) — who will soon be experiencing a series of tentative romantic encounters. It’s a testament to Riedel’s talent that their complicated love affairs become an opening to examine small-town poverty, female sexuality, and the ways we learn about relationships from our family’s mistakes. But after first resisting the urge to make the Garcias’ misadventures adorable, Riedel turns her naturalistic drama into Sex and the City, coupling the nicely nuanced women with caricatured men who are either lovable saints or horny buffoons. The exception is Blanca’s unpredictable roundelay with a dashing but manipulative out-of-towner (Leo Minaya) — indeed, theirs is the only relationship that possesses the random strangeness of real life, sparking hope that Riedel will continue to mine similarly compelling terrain in the future by trying to understand her male characters as deeply as she does their female counterparts. — Tim Grierson