1935 The air is already poisoned with anticipation of the upcoming war. But in the outskirts of Prague, in a medieval castle, no less evil lies dormant. It contains the “devil’s six”—murderers renowned for their cruelty. A young psychiatrist, a student of the legendary C. Jung, Victor Kosarek comes to the hospital in the hope of revealing the nature of evil and discovering the aspect of the devil in these patients. Meanwhile, Prague is shaken by a series of brutal murders committed by a maniac known as the Leather Apron. Victor tries to connect these murders and the dark secrets of his patients. But perhaps the devil himself is involved here...