High School DxD, Vol. 9 (light novel)

It's finally time for the school trip to Kyoto. Pillow fights, midnightconfessions...and it would be bad manners not to peek into the girls' bath,right? Issei is on cloud nine just thinking about it, but as soon as hisclass arrives, a brigade of monsters launches an attack, quickly turning anexciting excursion into a battlefield! It seems like a misunderstanding, butcould there be more to all this than meets the eye?