1892. In the forests of Vladimir Governorate, a victim of a ritual murder committed according to an ancient pagan rite is found. A detective from Moscow comes to investigate the case, and, in his search for the criminal, he must step by step unravel a tangled mass of local secrets—hidden facts and unsaid truths of the residents of a neighboring village. There, they believe that a water spirit lives in the pool, and that among the people a cannibal has appeared.