Ruben convinces Romy, a German army pilot, to show them evidence of supernatural phenomena on the Poppenberg mountain where the Pied Piper was said to have disappeared with the children in medieval times. In their search for further clues, Inspector Erik Zastrow impedes their investigation. But Ruben's father is not their only problem as Finja, Jannik and Ruben are attacked by ghost children. Meanwhile, Dr. Jamila Jost, Romy's mother, has a terrible premonition.