At the center of the events in the Russian mystical series "Sergei vs. the Unclean" is an unusual priest. He hunts down the forces of evil in a time of innovative technologies. The main character was long ago expelled from the church, after which he found a new calling - to deal with evil. During the pursuit of the unclean, Father Sergei encounters detective Katerina. She has only just begun to discover this supernatural world. The investigator asks the former priest to help her in investigating a strange crime.