In Soul Society strange things are happening with the Shinigami's Zanpakutou; Byakuya is cut by Senbonzakura during training, Hitsugaya can't communicate with Hyourinmaru and Haineko refuses to show herself at all to Matsumoto. However, it soon emerges that this is just the tip of the iceberg when Komamura is attacked by his own Zanpakutou during a hastily assembled emergency meeting. A mysterious man called Muramasa then explains that he has 'freed' the Zanpakutou giving them physical form and that he plans to bring an end to the 'Shinigami's rule'....

Rukia manages to escape to the Real World, despite being pursued by Sode no Shirayuki. She then informs Ichigo and the others about the events that have taken place in Soul Society involving the Zanpakutou, including the apparent disappearance of Byakuya.

Rukia returns to Soul Society in order to find out what happened to her brother, but soon encounters Sode no Shirayuki instead. Unfortunately for Rukia the fight does not go in her favor and Ichigo is forced to intercede on her behalf. However, in the end Rukia decides that this is a battle she must settle for herself regardless of what that may mean...

Ichigo and Muramasa face off but soon Muramasa is able to turn Zangetsu against his former master. However, in doing so Ichigo's Hollow self starts to take over something which Muramasa did not anticipate...

Everything is Soul Society is still in chaos. Everyone is still looking for Zanpakutous while Hisagi finds his Zanpakutou, Kazeshini and Renji, Zabimaru which is really surprising for him. They start to battle. Rukia is hospitalized and regains consciousness while Muramasa comes into Ichigo's soul and calls out Ichigo's inner hollow.

Renji continues to face off against Zabimaru whilst Hisagi fights against Kazeshini. Meanwhile, in Ichigo's soul Muramasa and Ichigo's Hollow self battle for control. However, when his other half gets into trouble Ichigo steps in to save him.

Kazeshini is just about to finish off Hisagi when Kira arrives to save him. Meanwhile, Ichigo faces off against Zangetsu and Renji continues his fight with Zabimaru. However, the Shinigami are both shocked when their Zanpakutous decide to use Bankai.

Ichigo tells the Captains what he has learned about Muramasa and how to regain control of the Zanpakutou. Later Oomaeda encounters Gegetsuburi and Hozukimaru whilst on his way to research Muramasa. However, before a fight can start Ichigo and Ikkaku arrive. Then before Ikkaku and Hozukimaru can face off properly Soi Fon and Ukitake arrive along with the covert ops division to try and capture the Zanpakutou....

Whilst searching for Byakuya, Ichigo encounters Haineko and Tobiume. However, before Ichigo can get serious about the fight Matsumoto and Hinamori arrive to take on their own Zanpakutous. Ichigo then decides to leave the fight to the girls and continue his search only to encounter Hyourinmaru shortly afterwards....

Matsumoto and Hinamori continue to fight against their respective Zanpakutou, but it is only by working together that they are able to defeat them. Meanwhile, Hitsugaya faces off against an amnesiac Hyourinmaru...

Kurotshuchi uses Gegetsuburi to continue his research into the Zanpakutou materialization phenomena. Meanwhile, Ichigo runs in to Muramasa whilst searching for Byakuya. However, just when it looks like Ichigo has the upper hand Senbonzakura intervenes. Although it is a tough fight it looks like Senbonzakura has lost until Byakuya arrives and attacks Ichigo!

Following his apparent defection, Byakuya is order to kill Sode No Shirayuki in order to prove his loyalty. With that task complete he then heads to the 6th squad headquarters with Senbonzakura where he encounters Rukia and Renji. Whilst Zabimaru takes on Senbonzakura, Renji attempts to defeat Byakuya....

As Ichigo faces off against Senbonzakura Renji is determined to finish his battle with Byakuya. Meanwhile, Ayasegawa and Ikkaku finally get to fight Ruri'iro Kujaku and Houzukimaru. The rest of the Shinigami also square off against the Zanpakuto.

Isane and Iba come face to face with Ashisogi Jizou, Tobiume and Haineko. It is then up to Hinamori and Matsumoto to help them out. Soi Fon continues her fight against Gonryoumaru and Tengen but things quickly become more complicated when Suzumebachi joins the fray. Ayasegawa is also having a hard time in his fight against Ruri'iro Kujaku. Meanwhile, Ichigo and Senbonzakura are both going all out to end their own fight.

Kenpachi finally arrives to join the fight after getting lost on his way back from Rukongai. He then proceeds to decimate the surrounding area so that he can fight the strongest opponent there, Byakuya. Meanwhile, Ayasegawa decides that it is time to go all out against Ruri'iro Kujaku.

The arrival of Ashisogi Jizou cuts short both Kenpachi's and Ichigo's fights. Meanwhile, Soi Fon continues her battle with Suzumebachi and is forced to use Shunkou to counter her opponent's maneuverability...

Yoruichi has discovered where Captain-Commander Yamamoto is being held. As such Ichigo, Kenpachi, Ukitake and Kyouraku accompany her on a dangerous mission in to enemy territory to rescue him.

Whilst trying to rescue Captain-Commander Yamamoto Kyouraku faces off against Katen Kyoukotsu, Ukitake takes on Sougyo No Kotowari, Kenpachi fights against Gonryoumaru and Tengen and Yoruichi is left to deal with Haineko and Tobiume. However, it soon becomes clear that the Zanpakutou are simply trying to delay their opponents as long as possible. Meanwhile, Ichigo is once again forced to fight Muramasa.

Now in possession of Ryuujin Jakka, Muramasa heads to Karakura Town to revive his former master Kouga. However, he is interrupted by Orihime, Ishida and Sado. Meanwhile, Ichigo and the others are trapped in Soul Society and it is up to Hyourinmaru and Hitsugaya to save them.

While Yamamoto, Kyouraku, Hitsugaya and Ukitake deal with Ryuujin Jakka, Kenpachi is finally enjoying his fight against Gonryoumaru and Yoruichi shows Haineko and Tobiume why she is known as the Goddess of Flash. Meanwhile, Senbonzakura and Rukia arrive to join the fight between Muramasa, Ishida, Sado and Orihime.

Several hundred years before the last episode Kouga Kuchiki is caught in the midst of a Shinigami civil war. Kouga together with his zanpakutou Muramasa quickly makes a name for himself and soon becomes a problem for the leaders of the rebel faction. As such he is set up for a crime he did not commit and before Ginrei can clear his name he escapes with Muramasa's help and starts a rebellion of his own.

Having escaped from prison Kouga exacts his revenge on the Shinigami who betrayed him. However, that is not enough and he decides to exact his revenge on the entirity of Soul Society. Ginrei and Yamamoto must then work together in order to stop his rampage and seal him away.

Byakuya reveals that his betrayal of the Shinigami was simply a ruse in order to discover Kouga's location. Although it seems that Byakuya has the upper hand over his Zanpakuto-less enemy, Kouga's unique ability soon evens the odds.

While Byakuya finishes dealing with Kouga, Ichigo, Rukia, Orihime, Ishida and Sado are left to deal with Muramasa. However, now that he has transformed into a Hollow Muramasa is much more powerful and even with Byakuya's help they may not be able to stop him.

The Shinigami and their newly deprogrammed Zanpakuto arrive to join the fight against Muramasa. However, they first have to defeat the seemingly endless number of Menos that have also appeared. Things are further complicated by the squabbling between the Shinigami and their Zanpakuto and the animosity towards Byakuya.

Ichigo and Muramasa are trapped in the remnants of Kouga's inner world where they finish their fight. Although Ichigo quickly figures out the secret behind Muramasa's attacks he requires Zangetsu's help in order to defeat him. However, they are quickly running out of time to settle the score as the realm starts to crumble around them.