The long-awaited meeting with his mistress did not foretell anything tragic, and even the strange place and time did not bother Oleg. But, having arrived at the appointed place, Oleg meets another woman, and this woman turned out to be dead. Nina never came to the date, but the next day she burst into Oleg’s house and, saying that someone was trying to kill her, asked for help. Oleg decides to find the killer based on one single clue...