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.

Derrick was a German TV series produced by Telenova Film und Fernsehproduktion in association with ZDF, ORF and SRG between 1974 and 1998 about Detective Chief Inspector Stephan Derrick and his loyal assistant Inspector Harry Klein, who solve murder cases in Munich and surroundings.