During the traditional carnival celebrations, the dead body of a young girl is found near the small town of Bellinzona, in Southern Switzerland. The officers engaged in the case find themselves investigating crimes rooted in a past full of shadows.
Even though his identity has now been revealed, the serial killer has no intention of giving up. The murderer is in fact determined to carry out his revenge at all costs, striking the last inexorable blow. Will detective Blum's team be able to stop him in time, revealing once and for all the truth of yesterday and today?