A mysterious reiatsu (spiritual particle) explosion occurs in the center of Seireitei in Soul Society, causing it to be destroyed. At the exact same time, a major change overwhelms Kuchiki Rukia, which leaves her losing something important inside. Urahara Kisuke sends Kurosaki Ichigo to Soul Society to investigate the disturbance. Upon reaching Seireitei, Ichigo is set upon and attacked by shinigamis, once allies, who have no memory of him and Rukia.