Nele Fehrenbach and Paul Schott have never made such a strange discovery before: a sailing boat that had long been reported missing is drifting on Lake Constance - and on board is a TV star who is also missing, but who simply cannot remember how she got there. It quickly turns out that Nana von Lohe is the daughter of a deceased famous plastic surgeon who ran his clinic on the lake. When the police deliver Nana to her family, they get their first surprise. Instead of reacting with relief and joy, Nana's sister Benita and stepmother Ilsa seem rather uncertain and nervous. Curious, the police, supported by their Swiss colleague Captain Aubry, uncover a number of inconsistencies. Was medical malpractice being covered up? Benita von Lohe, who took over the clinic from her father as a surgeon, would be particularly interested in this. And who is the great unknown who is interested in the clinic? Did the stepmother want to get rid of the youngest child so as not to have to share the inheritance? Finally, it is the hands-on Mechthild Fehrenbach who, with her love of Baden cuisine, discovers a crucial clue. Nana von Lohe occasionally helped TV chef Eckehard Prinz as an assistant. And then she suddenly disappeared again.