Sauerland, autumn 1995: In the middle of the forest on the Wilzenberg, a walker finds the body of high school graduate Sonja Risse. However, the fact that the killer left a music box with the lullaby "Hush Little Baby" at the crime scene does not lead to a clear solving. 25 years later, the investigative journalist Stefanie Schneider, known as "Mütze", made a surprising discovery in Cologne. In a disused multi-storey car park, she films an undressed corpse of a man with a music box running next to it! When her colleague Jan Römer, who reported on the spectacular Sonja case as a young journalist in 1995, recognizes the melody from back then, he immediately believes there is a connection. He goes to Wilzenberg with his ambitious colleague to interview Sonja's mother Maria, her former teacher Waldheim and her best friends. The more the journalists compile, the clearer the contradictions and gaps that the investigators should have noticed at the time.
16-year old Steffi just graduated from high school and is very much looking forward to her class trip to Paris where she has promised her boyfriend Fabian the romantic night that she has kept him waiting for so long. Her lifelong plan to join the police forces is already set up, her adult life is right around the corner. At a routine health check-up, just before the trip to Paris, Steffi and her parents are faced with a shattering diagnosis ...