The Eminence in Shadow, Vol. 4 (light novel)

"The specter of war hangs thick in the air of the Oriana Kingdom, where Princess Rose is expected to wed Duke Perv. This supposed marriage cannot and will not stand, though, as it would throw a major wrench in a certain shadowbroker's plans. Not one to miss an opportunity for sleuthing, Cid makes his way to the royal capital to put a stop to the ceremony, but are there even bigger schemes at work behind this unholy matrimony?"--Dust jacket flap.