Fifteen-year-old Felina Jagow disappeared without a trace on her way to school a month ago. The private detective Alexander Zorbach, hired by her mother, found an online music service through which Felina constantly listened to music. Unexpectedly, the playlist was updated only a few days ago. Perhaps Felina, using songs, is sending encrypted clues about her whereabouts and a path to rescue. Zorbach tries to unravel the mystery of the playlist without realizing that his search—and solving the musical puzzle—will turn into a nightmare for him. Ahead is a merciless fight against time, in which the chances of success are extremely slim.