An ordinary boy, Kostya Blagov, could not even imagine that trying to save his parents’ marriage would lead him to another world. A world in which the heroes of Russian fairy tales are revealed from an unexpected side. In which magic coexists with intrigue and betrayal. In which a new war unfolds - for the return of Koshchei the Immortal. Will Kostya, who finds himself at the epicenter of this war, be able to return home? And will he want to - after everything he learns about himself and about the world that has opened up to him?