Season 1

His first case takes him to Berlin. Prof. Dr. Bernhard Voss, a luminary for rare autoimmune diseases at the Berlin University Hospital, is said to have raped a nurse. The evidence is overwhelming; even Dengler does not believe that he can do anything for Voss. Voss tells of a major conspiracy by the pharmaceutical industry against him.

The security authorities are not investigating the perpetrators, but rather the people around the victims of the NSU murder series, files are being shredded, the Office for the Protection of the Constitution has its fingers in everything... What if this is not just a failure of the authorities? Who is protecting the murderers?

Dengler is commissioned by Dr. Larson, who advises waterworks companies around the world, to find EU Commissioner Kolidis, who has disappeared since his sailboat exploded off the coast of Athens. Dr. Larson believes that it could have been an assassination attempt. When Dengler arrives in Athens with Olga, whom he has promised a short vacation in Greece, it becomes clear that the entire family must have fallen victim to the attack. However, there is still no trace of Kolidis' body or that of his son Jannis. Dengler and the computer hacker Olga find evidence that suggests that Kolidis was on the trail of the dark machinations of an energy company involving the privatization of the water industry.

Shortly before his son Jakob's wedding in Stuttgart, the former BKA target tracker and private detective Georg Dengler is asked for help by hacker activist Olga. Olga's friend Anne, an investigative journalist, sent her information on the darknet about secret blueprints for microwave weapons, lists of names of Bundeswehr officers and photos of tortured men. Shortly afterwards, she was shot by unknown assailants. At the same time, Anne's informant, Bundeswehr officer and Afghanistan veteran Florian Singer, is involved in a near-fatal accident in his car. Dengler and Olga get on the trail of the secret Fahrenheit program of the BND and Bundeswehr, led by Werner Kempf, and Katharina Petry's initiated research into microwave weapons at MeySis AG. Dengler and Olga stir up a hornet's nest of illegal weapons tests and international arms deals.

The hacker Olga asks the private investigator Dengler for help after a friend's baby was bitten by a rat at night. She suspects that the real estate investor Jan Kröger is behind the matter, who wants to evict the old tenants from the Kreuzberg building. The former BKA target investigator is supposed to uncover the eviction scandal in which the tenants are terrorized using criminal methods...