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.

As the Shinigami battle the Zanpakutō Spirits, 3rd Division Lieutenant Izuru Kira defeats Kazeshini, only to be attacked by Wabisuke. Meanwhile, 11th Division Captain Kenpachi Zaraki arrives at the battlefield.

11th Division Captain Kenpachi Zaraki arrives and defeats Wabisuke before moving on to 6th Division Captain Byakuya Kuchiki. Meanwhile, 11th Division 5th Seat Yumichika Ayasegawa defeats his manifested Zanpakutō Spirit, Ruri'iro Kujaku.

As 11th Division Captain Kenpachi Zaraki and 6th Division Byakuya Kuchiki fight, 11th Division Lieutenant Yachiru Kusajishi chases Ashisogi Jizō before 12th Division Captain Mayuri Kurotsuchi forces his Zanpakutō Spirit to self-destruct and tells others to not interfere. Muramasa takes Byakuya to see Captain-Commander Genryūsai Shigekuni Yamamoto, who is inside of a barrier guarded by a dark-haired woman, two white-haired boys, and a cloaked figure.

A group of Shinigami attempt to rescue Captain-Commander Genryūsai Shigekuni Yamamoto, but they are held back by several Zanpakutō Spirits. Meanwhile, Ichigo Kurosaki arrives at the barrier surrounding Yamamoto and prepares to destroy it.

As Yoruichi Shihōin, 8th Division Captain Shunsui Kyōraku, 11th Division Captain Jūshirō Ukitake, and 11th Division Captain Kenpachi Zaraki continue to fight against the Zanpakutō Spirits, Ichigo Kurosaki frees Captain-Commander Genryūsai Shigekuni Yamamoto, only to learn this was all part of Muramasa's plan.

Captain-Commander Genryūsai Shigekuni Yamamoto and the others are held back by Ryūjin Jakka's flames as Muramasa attempts to free Kōga Kuchiki.

11th Division Captain Kenpachi Zaraki faces off against Tenken's Bankai, Kokujō Tengen Myō'ō, as Muramasa frees his master, Kōga.

Kōga Kuchiki's past is revealed.

6th Division Captain Ginrei Kuchiki and Captain-Commander Genryūsai Shigekuni Yamamoto are forced to seal Kōga Kuchiki away. In the present, 6th Division Captain Byakuya Kuchiki stops Kōga from killing Muramasa.

As Senbonzakura reveals the truth about 6th Division Captain Byakuya Kuchiki's betrayal, Byakuya fights against Kōga Kuchiki. Meanwhile, Muramasa loses controls and unleashes hundreds of Gillians.

6th Division Captain Byakuya Kuchiki defeats Kōga Kuchiki as Muramasa loses control and transforms into a Hollow version of himself. As Ichigo Kurosaki battles Muramasa, several Shinigami and their Zanpakutō Spirits arrive to help.

The Shinigami and their Zanpakutō Spirits try to deal with the Gillians.

Ichigo Kurosaki defeats Muramasa, and the Zanpakutō Spirits return to their original forms.

A party is being held at the Kuchiki Manor when two rogue Zanpakutō Spirits, called Tōjū, attack and disrupt the party.

10th Division Captain Tōshirō Hitsugaya battles a Tōjū which has been absorbed by a Hollow.

6th Division Lieutenant Renji Abarai and his Zanpakutō Spirit, Zabimaru, must defeat a Tōjū, but Hebi wants freedom.

A group of Shinigami must go into the sewers to fight a Tōjū. They are aided by a Zanpakutō Spirit who has been living in the sewers.

Kazeshini has a change of heart when he is forced to look after a baby.

Orihime Inoue must help a transfer student who is being controlled by a Tōjū.

Haineko falls for a Tōjū who is fully aware. However, when he loses control, Haineko decides to defeat him herself.

Zabimaru and Senbonzakura are trapped in the Shinigami Research and Development Institute.

8th Division Lieutenant Nanao Ise tries to relate to the violet-haired girl while they battle a Tōjū.

The Zanpakutō Spirits struggle with the final Tōjū until their wielders arrive to help.