When, during the carnival celebrations, the body of Eleonora Fontana, daughter of a well-known politician, is found in Bellinzona, detective Blum decides to put together a special team to tackle the complex investigation. In fact, the crime seems to have its roots in a past full of shadows and never-healed wounds.

The recent threats addressed to the victim's father lead detective Blum and his team to investigate the suicide of an important industrialist. At least until a second corpse is found, presenting traces attributable to the case of a ruthless serial killer who died eleven years earlier.

Now that the link between the Rochat case and the murders of the girls is evident, the detectives decide to start again with investigations from the past. Thus they discover the identity of two witnesses of the old serial killer suicide. But what happened to the third? And where is his daughter now?