Meet Dr. Vasily Ottovich Falk. An esthete, a pedant, a skeptic, a complete bore - and a reluctant detective. In a holiday village on the coast of the Gulf of Finland, where he moves in the summer from St. Petersburg, an elderly widow is found dead. The day before her death, she complained to Falk that a gray monk appeared in her garden at night - a sure harbinger of death. But the doctor quickly realizes that this is not a matter of gloomy omens, but of a real murder. And the further Vasily Ottovich tries to stay away from the investigation, the more he becomes drawn into the search for the criminal, because it quickly becomes clear that almost every resident of the dacha village had reasons to wish harm to the deceased.