Ichigo Kurosaki's school is attacked by strange spirits called Unforgiven (Togabito), revealed to have escaped from Hell, and Rukia Kuchiki and Renji Abarai are sent to investigate. Ichigo's family is targeted by the Unforgiven, who are led by Shuren, and Ichigo's younger sister Yuzu Kurosaki is abducted. An Unforgiven named Kokutō saves Karin Kurosaki from being abducted as well, and convinces Ichigo to accompany him and the Soul Reapers to Hell to save her. When they are attacked by monsters called Kushanāda, the guardians of Hell, on the journey, Ichigo's Hollow mask begins to spontaneously manifest. Kokutō warns him to avoid using his mask lest he lose control and hollowfy entirely, and tells him that the Kushanāda torture Unforgiven for their sins by killing them, as Unforgiven continuously revive, and that spirits killed in Hell become Unforgiven themselves.
In Karakura Town, unidentifiable spirits begin appearing en mases. While attempting to deal with these strange souls, Ichigo Kurosaki and Rukia Kuchiki meet Senna, a mysterious shinigami who wipes out most of them. Senna refuses to answer any questions, so Ichigo is forced to follow her while Rukia tries to find out what's going on.
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 attacked by his ally shinigamis
When an artifact known as the "King's Seal" is stolen during transport from Soul Society, Hitsugaya Toushirou is assigned to retrieve it. Toushirou goes missing after a battle with the thieves, leading Seireitei to suspect him of treachery. They order his immediate capture and execution. Unwilling to believe him capable of such a crime, Ichigo, Rangiku, Rukia, and Renji set out to find Toushirou.