Wiesbaden's historic cityscape can boast another architectural monument. A dilapidated city villa has been identified as the design of a famous Bauhaus architect. However, the discoverer, architect Moritz Fischer, cannot enjoy his fame for long: in the midst of the hustle and bustle of the Rheingau Wine Week, he is cold-bloodedly shot. Norma Tann, a former chief detective and recently turned private investigator, becomes a witness to the crime. Meanwhile, she has other concerns: her soon-to-be ex-husband Arthur got out of the car in the middle of a nighttime forest after an argument. Since then, there has been no trace of him.