The mafia boss Di Peena controls the protection racket in a business district. Owners who refuse to pay are intimidated by his men. By chance, Max and Dobbs witness a money collection.

By a lucky coincidence, Dobbs gets off a public bus before a poison gas attack kills all the passengers. Unfortunately, the police now suspect Dobbs of the perpetration. He flees and asks Max and Claudia for help.

The dubious meat wholesaler Winkelmann is suspected of smuggling drugs. Winkelmann's former secretary agrees to testify against her ex-boss in court. A witness protection program is supposed to protect her from attacks.

Casual thief Frederico Spinosi only clears out apartments whose owners are deceased. During one of his burglaries, he breaks open the safe of a recently murdered prosecutor. This causes trouble for two corrupt commissioners.

A truck speeds through the streets of Cologne and drives into the sold-out Kölnarena. Shortly after the crash, an anonymous caller contacts the police chief and demands the release of imprisoned war criminal Mirco Drusic.

Claudia receives information from a bodyguard about a corruption scandal involving a high-ranking politician. When she comes home, the bodyguard is lying dead in her bed. Claudia asks Max for help.