On November 22nd, 2010, ten missiles strike Japan. Known as "Careless Monday", this attack does not result in any apparent victims, and is soon forgotten by almost everyone. Then, three months later... Saki Morimi, a young woman currently in Washington D.C. on her graduation trip, is saved by a mysterious man, who has lost his memory, and has nothing except for a gun and a phone with 8.2 BILLION yen in digital cash.