Tatyana Sadovnikova goes to the waters, to a luxurious sanatorium. She likes everything there - the treatment, the service, and nature. But after several serene days, Tanya becomes an accidental witness to the strange death of a patient in a mineral “pearl bath”. No traces of violence were found on the body of businessman Nikolai Kuznetsov, and the Czech police closed the case, returning a verdict: heart attack. After which Kuznetsov’s colleagues from the security agency of his concern, the widow, as well as the restless Tatyana take over the investigation...