In Soul Society, Mayuri Kurotsuchi is attacked in his laboratory by a pair of mysterious siblings wielding a scythe that erases his memories. In a frightened panic, Kurotsuchi damages a machine, which causes a massive reiatsu explosion that covers much of Soul Society in a milky layer of reiatsu in the form of a giant rampaging river of serpents, killing and freezing many Soul Reapers, including Kenpachi Zaraki. Rukia Kuchiki is confronted and attacked by the siblings, erasing her memories and everybody that has memories of her, and is carried away to a rundown area of Rukongai by the siblings. Seemingly everyone in Soul Society has their memories of Rukia erased.
The 10th Division, led by Tōshirō Hitsugaya and Rangiku Matsumoto is sent to escort an artifact known as the "King's Seal", which is stolen during transport from the Soul Society by an unidentified and masked Soul Reaper and two mysterious Arrancar resembling girls who control fire and lightning. During the attack, Hitsugaya corners and seems to recognize the Soul Reaper, who wounds him and leaves. In the middle of battle, Hitsugaya abandons his post to pursue him and leaves his squad behind to fend for themselves. After the battle, Soul Society suspects Hitsugaya of treason and orders his immediate capture. The whole 10th Squad is then put under house arrest at which time they can surmise whether or not the division should be abolished.
A plus soul is chased by a hollow in a local park. Ichigo Kurosaki and Rukia Kuchiki appear and dispatch of the hollow and send the soul off to Soul Society. Comically, Ichigo finds his body inspected by medics, having turned into a Soul Reaper without placing an artificial soul within his body. He escapes from the scene with the aid of Rukia. Soon after, unidentified ghost-like spirits begin appearing in Karakura Town. A mysterious Soul Reaper who calls herself Senna appears and begins destroying the spirits. Ichigo and Rukia return to their Soul Reaper forms (Ichigo this time through the use of Kon, a mod soul) then confront her, but she refuses to answer any questions and leaves. In the battle, Kon notices a figure wearing dark armour among the spirits. Ichigo follows Senna while Rukia returns to Soul Society in order to search for answers.