When the body of American William Fishkin is discovered in a forest near Darmstadt, detectives Steffen Horndeich and Margot Hesgart are faced with a mystery: Why was the man killed? And why was he even in Germany? Fishkin worked as a private investigator, but his last stay in Hesse was purely personal - he was searching for his biological father. Although the father immediately acknowledged his paternity, something seemed off. After all, why did Fishkin inquire with the American police about mysterious deaths from forty years ago? Gradually, Horndeich and Hesgart begin to uncover a dark secret.