In a prehistoric underwater cavern off the coast of Marseilles are the first human engravings known to man. Among them is a crude drawing of a three-fingered hand, which has long puzzled archaeologists. Is it a hunting signal? A mystic sign invoking the spirits? Or is it, as many believe, evidence of ritual amputation in a Shamanistic world? The one who names himself 'The Hunter' apparently believes the latter. Driven by strange voices to kill and mutilate, he severs the body parts of his victims - and always signs his horrific crimes with a drawing of a three-fingered hand. The identity of this brutal killer is unfathomable, but Michel de Palma, of the Marseilles murder squad, has never lost a case, and he is not going to start now.De Palma heads to the University to investigate, but the clique of pre-history professors he encounters are as secretive as the cave-drawing itself. Slowly and alone, de Palma unravels a mystery that dates back to the Ice Age - and comes closer to discovering the killer's identity. But the academic community protect their own, and de Palma is no longer welcome in their circle...