Matthäi, a senior detective with the
Zürich police, is about to take up a post in the Middle East when a call comes in that a peddler has found the body of a little girl in the woods. With the peddler he inspects the site and, when none of the other police volunteer, says he will tell the parents. Distraught, the mother asks him to swear that he will find the killer. He goes to the little girls' school, where another child points out a picture the dead girl had drawn. It shows a tall man in a long black coat, a large black car, a little girl, a horned creature, and some black hedgehogs. The villagers think the peddler was the murderer, as does Matthäi's successor who, after a long hard interrogation, gets a confession. That night the peddler hangs himself in his cell. The police consider the case closed. Matthäi, however, believes the peddler was innocent and that the culprit is a serial killer who has murdered two other little girls and may strike again. As he takes his seat in the airliner, the man next to him is eating chocolate truffles which look just like the hedgehogs in the drawing. Realising that the killer may have befriended the little girl with chocolates, he abandons his trip. When his successor dismisses his theory, Matthäi decides to solve the case on his own. A psychiatrist friend suggests that the drawing is true. Such a killer is intimidated by grown women, and gets his revenge by murdering little girls. He must be childless himself. Plotting the three murder sites on the map, Matthäi sees that they were all beside the main highway from Zürich to
Chur. The heraldic animal of Chur is the horned
chamois, which appears on its vehicle number plates. He rents a filling station on the road, where he takes the numbers of cars from Chur, traces their owners, and under various pretexts rings up to find out if they have children. Seeing a lonely little girl in the village, he befriends her, learning that her name is Annemarie and that her mother is alone and unmarried. He invites mother and daughter to live in the filling station and encourages the child to play beside the road. Driving from Chur to Zürich in his large black car, a businessman named Schrott sees Annemarie playing and stops at the filling station, though his tank is nearly full. Matthäi finds out his home number, where his wife says that her two sons are out in the world. A few days later, Schrott hides his car in the woods and in his long black coat entices Annemarie with a glove puppet. He tells her nobody must know of their encounter. When Annemarie is late back from school one day, Matthäi sees chocolate stains on her hands and finds hedgehog truffles in her pocket. He orders the mother to take the child somewhere safe and, buying a shop window dummy, dresses it in Annemarie's clothes. Laying his bait in the woods, he alerts the local police and they keep watch for the killer. Schrott, who is only the stepfather of his wife's sons, has a row with her and drives off with murder in mind. Thinking the dummy is a dead Annemarie, he screams in terror. When Matthäi approaches, Schrott attacks and wounds him, but is felled by a shot from the police. ==Cast==