On August 15, 1994, investigators from the Frankfurt homicide squad made a gruesome discovery. In a villa in Westend, six bodies were found - one man and five women, all strangled. The widow Helga Lindemeyer lives across the street and watches as the bodies are transported away. Long before the murders, she often sat by the window, keeping an eye on the villa. At first, she had no idea that the two homeowners, Ingrid and Gabor Bartos, who were also among the dead, were running a private brothel. Helga is shocked and is eager to learn more about the background of the murders.