Having received news of the death of his uncle, Gleb Korsak immediately went to the provincial town of Polessk. Boris Alekseevich Korsak died in a fire in the local history museum where he worked as director. According to the official version, there was an accident - the old wiring caught fire. But then they planted a note on Gleb: “Your uncle was killed”... It turned out that Boris Alekseevich was writing a novel - Gleb found the manuscript in a safe among the charred ruins of the museum. It told the story of a distant ancestor of their family, Galeb Corso, who had to fight demons in animal form. Having seen images of the creatures described in the novel in the city, Gleb realized: perhaps his uncle had learned more about them than he should have...