Sie ist auf dem Revier, um ihre Freundin vermit zu melden. Beide sind ursprnglich zum Italienischlernen aus der Schweiz nach Florenz gekommen und dann geblieben, um in einer nahen Kleinstadt illegal zu arbeiten. Seit drei Tagen ist die bildhbsche Monika Heer spurlos verschwunden. Als die Leiche des Mdchens unter einem Haufen Tonscherben entdeckt wird, ist auch Maresciallo Guarnaccia ratlos.

Sara Hirsch is a nervous elderly spinster who still lives in the flat above a long-standing Florentine antiquities shop in which she was raised. Frightened, she calls Marshal Guarnaccia for help, sure that strangers have been in her apartment. The marshal knows she is a lonely old woman but he is preoccupied with an investigation.

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.

All over Florence tourists were being robbed, cars stolen, and somewhere in the city terrorists were quietly at work. So the suicide of a Dutch jeweller looked like an open and shut case. Certainly, there were some slight discrepancies. But the only witnesses were a blind man, and an old woman given to vicious lying. Yet, the Marshal felt uneasy.

When Marshal Guarnaccia is called upon to investigate the murder of a young woman, he wonders if the girls father, Paoletti, might have had something to do with her death. Enlisting the help of a local journalist, Marshal Guarnaccia's investigations draw him into Florence's seedy underworld.