From what I can remember this novel background is in the future where game slowly blend to reality. There is a special 'dungeon/mission' when their country celebrate independence day, and they need to find the special 'npc' to open it. The first one to open this is Japan, and their mission story is about the movie 'Japan is sinking' (which is an old movie in this novel world). After the opening every person in Japan, every one who are Japanese nationality and every person who log in Japan server couldn't be contacted. And then the movie scenario really happened, the only one who survive is the one who have game pod Edit : there also a Valentine Day event (couple only) where every answer would manifest in reality, ex : a woman ask her boyfriend 'will he save her or his mother if two of them drown in river(or lake)', the boyfriend said that he will rescue her (after all he think that this is a game). But then it's happened in real life, the woman and her boyfriend mother both drown. The man then want to save his mother but every time he approached his mother (the girlfriend can swim but acting like she can't), he will be unexplainably pushed toward his girlfriend. The girlfriend still pretend to be drown but then stopped pretending and swimming to savety when the man failed to save his mother several time then have to saw his mother downing and he can't do anything.