The murder of Christoph Hassenzahl, the manager of a traditional dumpling factory, shook Weimar. Its remains are found in granulated form. Shortly after detectives Kira Dorn and Lessing have started the investigation, Hassenzahl's wife Roswita, who she thought was dead, reappears. It is said that she lost her memory in a tragic accident seven years ago and has since made a living as a toilet attendant in a motorway service station at Hermsdorfer Kreuz. Although the investigators find out that the descent from dumpling queen to toilet queen is true, Roswita is still suspected of murder. Did she really only regain her memory the day her husband was murdered? Roswitasnew partner Roland Schnecke swears that this is the case.
But he is also a shady figure, as evidenced by his expensive car, which he could never have afforded with his meager earnings. Is the sudden windfall related to the murder? The commissioners also meet Thomas Halupczok, a potato farmer whose existence was destroyed by Hassenzahl. He would also be capable of murder, especially since his lover Marion Kretschmar is the manager of a supermarket chain that exclusively sells the "Hassenzahler dumpling specialities" and has driven the company into financial ruin by giving notice. The dumpling broth that Kira Dorn and Lessing have to stir is cloudier than the Ilm.