The unsuccessful and financially troubled writer Umberto Designori discovers a historical document in the Ticino village of Montagnola. Suspecting that it was authored by the famous writer Hermann Hesse, who spent the final years of his life in Montagnola, he sets off for Calw. However, the town archivist and Hesse expert, Dr. Giebenrath, reveals to him that the document is a forgery. The following night, Designori falls to his death. The supposed Hesse letter has disappeared. Detectives Lola Kraft and Jasmin Stein of the "Mordkommission Calw" begin their investigation.