Life has mostly returned to normal for the high schooler who knows nothing but misfortune, Touma Kamijou. But in a stroke of unbelievably good luck, he manages to snag two tickets for an overseas getaway trip! Of course, Kamijou is a veteran by now and immediately searches for a sinister trap or a hidden downside to this strange turn of events.
Unable to find anything obviously wrong, he anxiously sets off with Index to visit Venice, the "City of Water." Could this actually be a chance to rest, sightsee, and maybe even have a heart-throbbing romantic rendezvous? Just as Kamijou begins to relax and enjoy himself, he can't help but notice some strangely familiar faces hanging around...Is everything really going Kamijou's way for once, or is there something more to this too-good-to-be-true adventure??