The Last Assassin starts in Barcelona, which was cool for me so soon after visiting there. Eisler steps away from the "Rain" pun title pattern, but only maybe because "Torrential Rain" and "Rain Clouds" and "Light Rain" and "Raining Cats and Dogs" don't sound very tough. Also, I can't remember from books 3 and 4, but The Last Assassin might be the first of the series to not be told exclusively from John Rain's point of view, which gives you a better feel for the ladies.