The roots of the latest case of Viennese criminologists lie in the emotional relationship between a high school teacher and her pupil. Love with the taste of forbidden fruit attracted the attention of an unscrupulous man who tried to blackmail the unequal couple. Blackmail, however, apparently became fatal to him. There is no need to search long to find out who would immediately benefit from his death. What will be important, however, will be whether the young teacher and Commissioner Moser come to the same suspicion as to the person of the murderer. Did the student in love decide to take a radical action, or did a strange coincidence intervene?