A mysterious Zanpakutō Spirit named Muramasa releases the spirits of many Zanpakutō from their swords and attacks Soul Society.

Ichigo Kurosaki battles against the manifested Zanpakutō Spirit of Sode no Shirayuki, who arrives in the Human World while chasing Rukia Kuchiki.

Rukia Kuchiki and Ichigo Kurosaki battle Sode no Shirayuki, and Muramasa reveals he is a Zanpakutō Spirit.

Muramasa releases Zangetsu, and Ichigo Kurosaki fights him as his inner Hollow begins to take control.

6th Division Lieutenant Renji Abarai is confronted by the spirit of his Zanpakutō, and Muramasa enters Ichigo Kurosaki's inner world.

9th Division Lieutenant Shūhei Hisagi fights his Zanpakutō spirit while Hollow Ichigo fights Muramasa and 6th Division Lieutenant Renji Abarai regains the ability to release his Shikai, Zabimaru.

3rd Division Lieutenant Izuru Kira aids 9th Division Lieutenant Shūhei Hisagi, who is fighting Kazeshini, while 6th Division Lieutenant Renji Abarai and Ichigo Kurosaki conclude their battles.

11th Division 3rd Seat Ikkaku Madarame and 2nd Division Lieutenant Marechiyo Ōmaeda encounter their Zanpakutō Spirits, and Ichigo Kurosaki spots 6th Division Captain Byakuya Kuchiki.

10th Division Lieutenant Rangiku Matsumoto and 5th Division Lieutenant Momo Hinamori battle their Zanpakutō Spirits, and 10th Division Captain Tōshirō Hitsugaya tells Hyōrinmaru what his name is while Muramasa limps through the Forest of Menos.

As 5th Division Lieutenant Momo Hinamori and 10th Division Lieutenant Rangiku Matsumoto conclude their battle, 10th Division Captain Tōshirō Hitsugaya tries to convince Hyōrinmaru he is his master, but the Zanpakutō Spirit does not believe it.

Ichigo Kurosaki attacks Muramasa, but Senbonzakura, and later 6th Division Captain Byakuya Kuchiki, shows up to protect him.

Muramasa has 6th Division Captain Byakuya Kuchiki perform a test of loyalty. Afterwards, Byakuya invades the 6th Division barracks and is forced to fight his lieutenant, Renji Abarai.

As Ichigo Kurosaki, 2nd Division Captain Suì-Fēng, and 3rd Division Lieutenant Izuru Kira begin their battles, 11th Division 3rd Seat Ikkaku Madarame fights and defeats his Zanpakutō Spirit, Hōzukimaru.