Christina Fehrmann asks Professor T for help in the investigation of a double murder. The murder of prosecutor Krämer an his wife identically resemble a ritual murder 15 years ago. Thanks to Christina and the now dead prosecutor, the alleged murderer was convicted and institutionalized. Still today, he asserts his innocence. Now T has to find out whether or not the man was wrongly jailed 15 years ago, or find the real murderer fast to save Christina's career.
—Katharina