Bleach Volume 20

Finding the members of the Central 46 Chambers all dead, Hitsugaya pursues Kira who reveals that Momo had also entered the Central 46 Chambers. Guided by Gin, Momo learns that Aizen is alive before her captain impales her with his zanpakuto. When Hitsugaya arrives, informed by Aizen that Gin was actually his co-conspirator, Hitsugaya unleashes his bankai to avenge Momo. But Aizen defeats Hitsugaya and almost kills him before Squad Four Captain Retsu Unohana appears, denouncing Aizen's treachery. Aizen then informs her that every Soul Reaper in the Soul Society has been under the hypnosis of his zanpakutō, with the exception of the blind Tōsen who is revealed to be Aizen's other accomplice. As Unohana's lieutenant Isane Kotetsu relays the revelation to all high-ranking Thirteen Court Guard Squad members, Aizen arrives to Tōsen's location after he brought Rukia and Renji. After Ichigo, Renji, and Komamura were all defeated, Aizen explains the entire execution was arranged so he can obtain the Hōgyoku, an orb that would allow him to gain hollow powers that was hidden in Rukia's gigai by Urahara. After extracting the Hōgyoku from her body, with the Thirteen Court Guard Squads surrounding them, Aizen and his accomplices use several hollows to escape into a portal leading to the hollows' world Hueco Mundo.

End of Hypnosis
Contains chapters 169 - 178.