Since being abandoned by their parents at age two, teen girl Amalie Nakajima and her older twin brother Taro have lived in the narrow streets of the small city of Yokohama. Sometime after turning sixteen, the twins and their two childhood friends Ryunosuke Akutagawa and his younger sister Gin have a brutal encounter in a building with six gunmen who injure them and kill the other eight teenagers, Katsumi, Rin, Sayaka, Shinya, Takahiro, Zenaida, Yuji & Nina. Filled with fury, Taro and Ryunosuke head outside to locate where the gunmen are and slay them all in a brutal fight during which the two teen boys receive more injuries. After the fight, they have a encounter with young criminal Osamu Dazai and physically say no to his invitation to join the large organization he is a member of, leading to him capturing Gin and Amalie alive.