After the mysterious disappearance of a refugee girl, a new crime occurs in snowy Vienna. Eight-year-old Elsie has gone missing. While the parents are acting extremely suspiciously, the ambitious minister of the interior senses an opportunity to use the crime politically for himself.

The police conduct a desperate search for the bodies of the missing children, while politicians use their helplessness to enforce security.

The children's bodies are found, and a necklace serves as the only clue towards finding their killer. Meanwhile, the city's underworld kicks into gear.

The Minister of the Interior resorts to more drastic means to achieve his political goals. In order to establish the identity of the third dead child, he has the entire city placarded with the portrait of the corpse. The atmosphere is heated. The Minister of the Interior declares the M case a public case. Meanwhile, the Romanian beggars set out to find the murderer.

As more children disappear, fear grows across the city. Meanwhile, the police think they are drawing close to the killer.

The streets of Vienna are deserted. The curfew imposed by the Minister of the Interior is accepted by the population without resistance. In the midst of this ghostly atmosphere, the police hunt for the perpetrator. But the underworld also remains active. It has its own method and lures the murderer with the children of Romanian beggars.