Tatyana Sadovnikova goes to the waters, to a gorgeous sanatorium. She likes everything there - and treatment, and service, and nature. But after a few 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 with a verdict: a heart attack. After that, Kuznetsov's colleagues from the security agency of his concern, a widow, as well as the restless Tatyana, take up the investigation...