In the casemates, the underground fortifications of Marburg Castle, the body of a young student is found. He was a member of the fraternity "Die Elisabethaner." Why did the young man have to die, and what is the secret surrounding Saint Elisabeth? Commissioner Nau delves deep into the history of Marburg and the student associations. The trail leads into the numerous dark corridors of the Marburg casemates. Can Nau solve the murder before more deaths occur?.