The year is 1959. In the city of Leningrad, an old lady, a dandelion of God from the "former", was poisoned by one of the apartment's inhabitants in a communal apartment. Then the culprit was never found. And now, half a century later, Maria Karavai takes up the investigation of an old murder. World-renowned cellist Ksenia Averintseva buys an apartment overlooking the Griboyedov Canal. Upon learning of this, her grandmother dies of a heart attack. By a fateful coincidence, she lived in that old apartment and was a suspect in an unsolved case. But Ksenia can't believe that her grandmother is a murderer. She asks Maria Karavai for help, and she agrees. Gradually unraveling the secrets of the communal residents, Masha and Ksenia are approaching the main mystery, which is deadly for those who live today. The story, which began as an amateur archival investigation, turns into an action-packed thriller. Hiding in the labyrinths of St. Petersburg courtyards and on the old forts near Kronstadt from the murderer who is chasing her, Maria Karavai is trying to find information lost in time bit by bit. Daria Desombre's detectives are distinguished by the presence of subtle intrigue, mystical secrets and a detailed excursion into history, culture and art. Desombre works painstakingly on each new book. Recreating the past, she reads memoirs, spends many hours in libraries and museums, and collects photographs of clothes and objects from past eras from family albums and magazines.