Peter Weir's haunting and evocative mystery is set in the Australia of 1900, a mystical place where the British have attempted to impose their Christian culture with such tweedy refinements as a girls' boarding school. After gauzily-photographed, nicely underplayed scenes of the girls' budding sexuality being restrained in Victorian corsets, the uptight headmistress (Rachel Roberts) takes them on a Valentine's Day picnic into the countryside, and several of the girls, led by the lovely Miranda (Anne Lambert) decide to explore a nearby volcanic rock formation. It's a desolate, primitive, vaguely menacing place, where one can almost feel the presence of ancient pagan spirits. Something -- and there is an unspoken but palpable emphasis on the inherent carnality of the place -- draws four of the girls to explore the rock. Three never return. No one ever finds out why. The repercussions for the school are tragic, and of course Roberts reacts with near-crazed anger, but what really happened? Weir gives enough clues to suggest any number of explanations, both physical and supernatural.