On the night of a severe thunderstorm in Saint-Marco, three people die in a similar way. It would seem that what is strange about this? Heart attack, it doesn't happen to anyone! But the fact is that one of them is an officer in the king’s retinue, and the second is an auditor of the treasury. This circumstance arouses suspicion among the head of the secret police. Count Raymond instructs Baron de Segur to investigate the circumstances of these deaths, and Mark, who initially took this assignment without much interest, suddenly learns that the deceased were victims of a magical attack. In addition, it turns out that not only these three suffered from the attack of an unknown sorcerer. Baron de Segur continues his investigation, in which he is helped by the young magician Philbertus. Will they be able to catch the mysterious killer and get their hands on an ominous artifact that kills from a distance?