Four years ago, Makoto Nakazawa lost family, friends, and even memory of the events during the outbreak of the Unknown virus epidemic in the Tohoku region of Japan. Now adopted by a female friend of his deceased father, he lives in the Shibuya district of Tokyo, struggling to rebuild a new life in a new land. However he doesn't suspect what Fate has for him when he accepts to go to a little (and not entirely fictional) island in the Inland Sea of Japan as correspondent for the newspaper club of his school, because that island is about to become one of the starting points of the second outbreak of the epidemic he barely survived once...