Ten years ago Isa (Henriette Confurius), the daughter of the von Gems brewery family, disappeared without a trace during a violent thunderstorm on the night of the school festival in Lotheim. There were no witnesses or indications - instead, for years only rumors, fears and open questions. Then suddenly Isa appears again, just like that - but with no answers. She cannot remember anything and thus takes away all hope of the redeeming truth. Isa's parents (Christian Berkel and Claudia Michelsen), her grandmother (Hildegard Schmahl), her brother (Rick Okon), they all have to come to terms with Isa's return after having struggled to get their lives under control again in recent years. The commissioner (Götz Schubert), who failed with his investigation at the time, hopes, however, to finally find out the truth.