An intriguing and exciting detective novel based on real events! The story of the first officially registered serial killer in Russia. 1909, St. Petersburg, a corpse was fished out of the Neva River early in the morning. The murder was committed in a particularly sophisticated way and apparently ritual. The next victim confirms this assumption. Konstantin Marshal, assistant chief of the metropolitan investigation department, is leading this complicated case, but the criminal masterfully confuses the tracks. Meanwhile, the killer is very close, and the danger threatens the beloved woman of the detective! How to solve a dangerous case and save your love?