At Professor Alexeyev’s country estate, the host gathers friends and family and acquaintances around an exquisite table. But the festive mood is shattered in an instant: the figure of his former wife, Marina, appears on the doorstep. She longs for a private conversation with her ex-husband, insisting that she must tell him something so important that it cannot tolerate the slightest delay. However, the fateful secret is not destined to be revealed: before Marina can utter the long-awaited words, her life is cut short under circumstances shrouded in the darkness of the unknown. An investigative team arrives at the scene of the tragedy. The victim’s sister, Tatyana Grushina, unable to accept the slowness and, as it seems to her, the superficiality of the official investigation, decides to take matters into her own hands. She understands that in order to find the killer, she must delve into the innermost depths of the past and solve the mystery Marina had carefully guarded for many years.
