Nikolai Pereyaslavsky is a young, capable detective who has a bright future ahead of him. But one day his path intersects with a mysterious person nicknamed the Jester, and his career, dreams, and family - everything collapses overnight. From an exemplary detective and a threat to lawbreakers, Nikolai himself turns into a criminal, whom all the gendarmes of the Empire are looking for. At this very time, in order to save his unlucky friend from hard labor, Pereyaslavsky agrees to find the missing daughter of the landowner. The former detective does not suspect how many dangers his journey to the ancient mountains of the Urals has in store for him, he does not know that the traces of the girl are lost on the borders of our world, near the wall of the mythical Fortress of the Moon...