A year before the events, Taisiya Yermolaeva planned to take a vacation with her fiancé on a river cruise. But the plans changed: he married someone else, and she realized she didn’t love him as much as she thought. After defending her candidate thesis, Taisiya decided not to cancel the trip and went on the cruise alone. On the boat she met new people and ran into an old friend. Soon strange deaths began happening around her, and she found herself drawn into an investigation. It seemed like a series of accidents—or like someone’s cunning revenge.