It features Herr Inspector Loman, who was also in M as the cop trying to catch Lorre before the underworld did. He's a neat character, a sort of German Inspecteur Maigret, and I'd have liked a series about him, though I suspect that such a series, if historically realistic, would have to have ended with him being fired and possibly arrested once his quiet stubbornness and honesty butted up against politics.