The charity gala at the police headquarters in Münster leads to a momentous revelation. During a magic trick by the amateur magician Prof. Boerne, the young Helena Stettenkamp explains under hypnosis that her recently deceased grandfather was poisoned. A scandal. Was the head of the Stettenkamp biscuit dynasty actually murdered? Inspector Thiel arranges for the body to be examined again. At the same time, a young dragon hunter falls from the sky in a forest near Münster. The autopsy reveals that he was poisoned with the same means as the company patriarch. How are the two murders related?