Police commissioner Julian Sellinger investigates the disappearance, probably kidnapping and/or death, of Sophie, daughter of Hessen's next LKA (state prosecution) president Herbert Wichert, from exclusive boarding school Erlengrund. He is forced to collaborate with LKA-agent Isabell Moosbach, who goes undercover as new sports and literature teacher as Karla Parker, but hides being an alumna until her father's sudden death, while her recently deceased mother received regular (hush?) payments the school benefactors' generous foundation, presided by Wilfried Maas, which may stem from the former GDR's communist party SED. Shortly after, brilliant but haughty and unpopular Felix Baumschulte's corpse, whose enigmatic photo manipulation art suggests he knew much, is found shot and floating in the lake, probably a staged suicide just before he was to proudly direct the school orchestra. Felix especially provoked Sophie's otherwise gentle class boyfriend Till Rückert, but Sophie was pregnant ...