Ravenous (1999)

Captain John Boyd has been sent to a remote outpost in Sierra Nevada following a military disgrace in the Mexican-American War. There, his group run into Colqhoun, a starving and half-frozen Scottish traveler who tells a wild tale of cannibalism. His group, it seems, was led astray by a guide, snowed into a cave, and finally descended to eating one another. He fled from the evil Colonel Ives. Boyd determines to apprehend Ives, but when he follows Colqhoun back to the cave, events take a more dangerous turn, and Colqhoun turns out to be not quite all he claimed to be.