A Different Time

How would things have been different if Harry and his compatriots had lived in the 20s instead of the modern era? Obviously they'd still get into apocalyptic situations way too often for any sane individuals, but how would the relationships between them change? Harry still has his PI business, but Murphy is his partner now since the force won't allow her to become an officer. They meet a young man who has been possessed by a light-hating demon, and after going to a speakeasy to try and find some information about who summoned the demon, Harry meets a nice businessman named Milano who offers him some help. He takes it gratefully, but then he realizes that the kind Milano is actually notorious mob boss Gentleman Johnny Marcone and everything begins to change.