Summer in 1679. In Vienna, the plague rages and spreads to Bavaria. Behind the Schongaus Kat Jakob Kuisl, a deadly ill man was out of the last power. Just before his end, he made a mysterious prophecy: Kuisl is said to be the only one who can save Kaufbeuren. The black rider plays the whistle there and forces the inhabitants of the city to dance. The murderer has two faces. Jakob Kuisl and daughter Magdalena set out on a dangerous expedition. In Kaufbeuren, other people die in suspicious circumstances. Were the victim of an epidemic or a refined murderer?