Bleach Movie 2: The DiamondDust Rebellion

A valuable artifact known as "King's Seal" is stolen by a mysterious group of people during transport in Soul Society. Hitsugaya Toushiro, the 10th division captain of Gotei 13, who is assigned to transport the seal fights the leader of the group and shortly after goes missing. After the incident, Seireitei declares Hitsugaya a traitor and orders the capture and execution of Hitsugaya. Kurosaki Ichigo refuses to believe this, and along with Matsumoto Rangiku, Kuchiki Rukia and Abarai Renji swear to uncover the real mastermind of the stolen seal, find Hitsugaya and clear his name. Meanwhile, a rogue Hitsugaya searches for the perpetrators and uncovers a dark secret regarding a long dead shinigami.

An artifact known as the "King's Seal" is stolen during transport from Soul Society by an unidentified Soul Reaper and two arrancar girls who control fire and lightning. Tōshirō Hitsugaya seems to recognize the Soul Reaper, who stabs him in the stomach; he then abandons his post to pursue him. Seireitei suspects him of treason and orders his immediate capture, with the possibility of disbanding the 10th Division should he be guilty.

Tōshirō is found unconscious by Ichigo, who knows that Soul Society is looking for him. Tōshirō refuses to explain what's happening, but Ichigo is attacked by the two arrancar before he can force the issue. Tōshirō continues to avoid capture, and things only look worse when the Soul Reaper thief, identified as Sōjirō Kusaka uses Hyōrinmaru, a sword identical to Hitsugaya's, to injure Shunsui Kyōraku. Tōshirō's capture is made top priority, and his execution is approved if he resists.

Meanwhile, back in the world of the living, Rukia has caught up with Ichigo. The gang exchange information, and Rukia reveals rather surprising, in depth knowledge of Hitsugaya's personality, as well as some rather accurate guesses as to what Hitsugaya plans to do next. During the talk, Ichigo realizes what might be troubling Hitsugaya.

Tōshirō eventually manages to track Sōjirō down, where it is revealed that the two managed to manifest the same zanpakutō. Because this is a taboo in Soul Society, they were forced to fight to the death. Tōshirō did not wish to but accidentally froze Kusaka in the fight. It was decided that Tōshirō was winner while Sōjirō was apparently killed, only to reincarnate in Hueco Mundo. Seeking revenge on Soul Society, he stole the King's Seal, which allows the user to freely manipulate time, space, and matter within a small space. Using it, Sōjirō teleports Tōshirō and himself to Soul Society, needing the power of Tōshirō's bankai to break the seal. When Tōshirō refuses, Sōjirō breaks the seal himself, becoming a dragon made of ice. However, because he lacks the control Tōshirō possesses, the power goes berserk and threatens to destroy Soul Society. With much help, Ichigo and Tōshirō manage to destroy Sōjirō's dragon form. Returned to his regular form, Sōjirō and Tōshirō have one last clash, ending in Sōjirō's defeat. Tōshirō is cleared of all charges and the King's Seal is restored, allowing Tōshirō to finally put his past to rest