There is little preamble to Cave of Forgotten Dreams. No attempt to graft a larger narrative (indeed, a narrative at all) on the picture, no lengthy introductions of the cast of scientists, archaeologists, and filmmakers with whom you'll spend the next hour and a half. The credits are quick and unadorned, and over them, the unique and unmistakable voice of director Werner Herzog intones, in his inimitable manner, the discovery of Chauvet Cave of southern France. The story is straightforward: a group exploring the area came across the cave, which had been long closed off from a rockslide. The...