Music is her life. 15 songs decide how long it lasts. A month ago, fifteen-year-old Feline Jagow disappeared on her way to school. Her distraught mother asks private investigator Alexander Zorbach, a former police detective, to discover her whereabouts. Despite a month having elapsed since her disappearance, Feline's music playlist was changed just a few days ago. Could a seemingly innocuous list of songs contain a hidden clue to where the girl is being held - and how she can be rescued - or is the truth something more sinister? Soon, the mystery of the playlist plunges Zorbach into a horrifying nightmare that mixes past terrors with new ones, and where no one's survival is guaranteed...