This book has 3.5 star rating. The humor is the previous books are nowhere to be seen, including cheesy one-liners by Harry Dresden. In fact, this is probably the most tragic Dresden book.
It starts innocently enough. Harry Dresden receives an offer he cannot refuse: a duel with a Duke of the Red Court of vampires. I do not need to mention that a vampire does not become a Duke without fighting a fair number of duels and surviving. Right after this, local mafia goons start doing their best to see Dresden bite the bullet. On a top of this, a representative from Vatican asks our supernatural PI to find a great artifact of faith stolen from Italy. Oh, and the woman Dresden loves has a new man in her life. In short, this is business as usual.