When the mathematics teacher discovers a love letter from his daughter, family father Felix Schneider is suspected of having a secret lover.
A young woman wants to know who is responsible for the death of her parents. Ten years ago, little Sonja and her brother Niki Schmitt lost their parents in a car accident. Mayor Gassner provided accommodation for the two at that time. Sonja now returns to her hometown to solve the death of her parents. She blames Mayor Gassner until she learns the whole truth.
