Real estate agent Mikhail spent a long time preparing the deal for resettling a ten-room communal apartment in St. Petersburg. But on the eve of the sale, in one of the rooms, under the floor, they discover a corpse.
Meanwhile, Lena, Mikhail’s wife, suspects that the incident is connected to events from her youth. While the investigation is underway, Mikhail and Lena’s relationship goes through one test after another: people from the past return, and the present hides plenty of riddles.