Norma Tann's new assignment takes the private investigator from Wiesbaden to the picturesque wine-growing region of the Rheingau and up to the heights of the Rheinsteig. Ruth Diephoff, a yoga teacher and widow of a Rheingau winemaker, cannot come to terms with the idea that her daughter Marika is supposed to have drowned in the Rhine. For the first time since her mysterious disappearance 15 years ago, there is a concrete lead that Norma wants to pursue: Kai K. Lambert was Marika Inken's lover. Did she go abroad with him? Marika's daughter, 17-year-old Inga, is also very interested in Lambert, as she is tormented by a burning question: Is he her biological father? Since a secret paternity test, she knows for sure that it cannot be Bernhard Inken, the owner of a media agency in Wiesbaden...