Doro is young, beautiful and a trained opera singer that gets by with occasional jobs. Her neighbour, a former criminal detective, is dying and she cares for him in his last moments. His dying wish is to see his son Michael. Doro fulfills the old man's wish and they meet for the first time since twenty years.

"Your colleague has more testosterone than Mike Tyson," Kozack is told and - even worse - has to admit that his interlocutor is right. He was always the alpha male on the beat! But since the BKA officer Mia von Weitersdorf and the Berlin police officer were welded together to form a team against their will, she shows him where the hammer hangs. Kozack had blown up an undercover operation for which Mia was responsible. A colleague was killed, a suitcase full of money and the designer drug "Green Devil" went missing. Mia and Kozack are put on leave - and continue their investigation together. After some initial friction, they realize that they complement each other very well: Kozack knows his way around the Berlin scene and Mia has a quick wit and excellent contacts "at the top". Kozack has to realize that Mia is an equal partner - a hard blow for the macho man.