The name of the Seibt family, manufacturers of baby supplies, represents happy families and a healthy world. Which makes it even more shocking when the dead bodies of the chief executive Edwin Seibt, his mistress Anuschka and his wife Carola are found. It looks as though Carola Seibt killed her husband and his mistress in a fit of jealousy and then took her own life. Except that Marie Brand, chief inspector in the Cologne homicide division, is convinced it didn't happen that way at all. She and her colleague Jürgen Simmel begin to investigate the case, and soon Marie comes to the conclusion that Carola Seibt was already dead when her husband and his mistress were shot.
Marie and Simmel track down a private detective called Martin Bremer, who was employed by Carola to keep Edwin Seibt under surveillance. And when Bremer is also found dead, it adds weight to the suspicion that Edwin Seibt and his mistress were murdered by somebody else.
The trail leads Marie and Simmel to the Seibts’ grown-up children, Hanno and Antonia. Hanno doesn't bother trying to conceal the hatred he felt for his father. Did he resort to murder in order to escape from years of subservience? Or was it Antonia Seibt’s husband, Steffen Probst, who appears to have married her as a career move, worked alongside her father, but now stood to lose his job in an impending merger?
As Marie and Simmel track down the killer it becomes increasingly apparent that the respectable facade erected by this deeply dysfunctional family is a complete sham - even though the Seibts’ lawyers do everything they can to foil the police investigation.