A serial killer is on the loose in the small town of Petrovice, murdering students at the local high school. The police are searching for the perpetrator, but they can't find any clues. Everything points to the masked killer targeting Karin Tomečková, whose parents were brutally murdered eight months ago. The murders are increasing, as are the number of suspects. The police are trying to catch the killer before it's too late. The killer could be anywhere.