Certain Magical Index, Vol. 15 (manga)

Touma Kamijou's life is one of perpetual misfortune, which is why no one is more surprised by his sudden stroke of luck than Touma himself! Having won a trip for two to Venice, the City of Water, Touma and Index are excited for a European excursion. But the Italian peninsula is the home of the Roman Orthodox Church, and when old friends and foes alike show up, Touma's hopes for a relaxing getaway might just get washed away!