Raisin Radcliffe and her brother, Geoffrey, stumble on a labyrinth of caves below an ancient dolmen near Collioure, a village on the craggy edges of the French Pyrenees. They tell no-one about their find. Then the mayor's five-year-old son is snatched by a violent cult and threatened with death if the village goes ahead with plans to allow tourists into its famous prehistoric cave, Grotte des Loups. Geoffrey becomes obsessed with finding the child...