Of course a vampire is simply a cannibal with good table manners, and Ravenous is a darkly atmospheric film about an epidemic of flesh-eating and the fearsome power that it brings. It takes place during the Mexican-American War, in an isolated U.S. Army outpost in the Sierra Nevadas, when a half-dead man (Robert Carlyle) staggers into the fort with the story of snowbound travelers, starvation and worse: We ate the oxen, then the horses, then a dog, then our belts and shoes . . Eventually one of the party died of starvation, and they ate him. Then they ate others . and by now the commander of the fort has heard enough, and determines to send out a party to investigate. All of this is shown in dark colors and a soundtrack of chimes and mournful cries; low, ominous, burbling percussion, and far-off female laments. Ravenous is the kind of movie where you savor the texture of the filmmaking, even when the story strays into shapeless gore.