Plot
Soul Reapers of the 10th Division—led by its captain Tōshirō Hitsugaya and vice-captain Rangiku Matsumoto—are sent to escort the "King's Seal". The rare artifact is stolen during transport by the deviated Soul Reaper Sōjirō Kusaka, and two girls known as Ying and Yang. Hitsugaya apparently recognized the Soul Reaper, who wounds him and leaves, and abandons his post to pursue the man while leaving his squad behind to fend for themselves. Later, Soul Society suspects Hitsugaya of treason, orders his immediate capture, and puts his whole squad under house arrest.
In the human world, Substitute Soul Reaper Ichigo Kurosaki is informed about the events happening in the Soul Society, and finds Hitsugaya, who passes out. Hitsugaya wakes up in Ichigo's house, and they are attacked by Ying and Yang. Ichigo fights, while Hitsugaya escapes and continues to avoid an attempt of capture by Soul Society. The suspect on him increases when Kusaka attacks a Soul Society's captain using Hyōrinmaru, a zanpakutō—special swords used by Soul Reapers—with identical powers to Hitsugaya's. Hitsugaya's capture is then made top priority and his execution is approved.
Through his wandering to avoid capture, Hitsugaya eventually manages to track Kusaka down, and it is revealed that the two managed to manifest the same zanpakutō. Because Soul Society does not allow the same zanpakutō to be wielded by different people, the two were forced to fight to the death. Hitsugaya did not wish to fight, but had no other option as Kusaka attacked, claiming that he was the only one worthy of Hyōrinmaru. The authorities concluded that Hitsugaya was the true owner of Hyōrinmaru and carried out Kusaka's execution. Kusaka died and was reborn as a Hollow in their world, Hueco Mundo. Once he learned of the King's Seal and its powers—which allows the user to freely manipulate time, space and matter—he started his plan of revenge against Soul Society.
Using the King's Seal, Kusaka teleports Hitsugaya and himself to Soul Society, needing Hitsugaya's power to break the seal. The Soul Reapers find and attack Hitsugaya and Kusaka, but are thrown back when Ichigo intervenes. As Hitsugaya refuses, Kusaka breaks the seal himself, after which he transforms into a giant dragon-like creature made of ice. However, because he lacks the control which Hitsugaya possesses, the power goes berserk and threatens to destroy Soul Society. A hoard of Hollows appears out of Kusaka's castle, which he had generated out of the Kings' Seal. While several Soul Reapers face the Hollows, Ichigo and Hitsugaya storm up to the central tower. After they destroy Kusaka's dragon-like form, Hitsugaya impales Kusaka. Hitsugaya is cleared of all charges and the King's Seal is restored. After the credits, he and Rangiku visit Kusaka's grave.
