Marshal Guarnaccia of the Florence carabinieri is first puzzled and then irritated when he is dragged into a last-ditch attempt to nail the Monster, a vicious serial killer who has ritually slaughtered seven courting couples in the most brutal of circumstances. But he is soon sucked into the horror and squalor of a multi-layered case that has confounded the authorities for over ten years. So when a case is made out against the wrong man - a monster in his own right who beats his wife and sexually abuses his daughter - who is going to admit it? Summoning the courage to speak out, the Marshal rapidly realises that no one wants to listen. It is more comfortable for everyone, even the wrongly accused man, if the blood-soaked vineyards keep their secret of what really happened on the Saturday nights of the new moon...