Bleach the Movie: The DiamondDust Rebellion

When an artifact known as the "King's Seal" is stolen during transport from Soul Society, Hitsugaya Toushirou is assigned to retrieve it.

Toushirou goes missing after a battle with the thieves, leading Seireitei to suspect him of treachery. They order his immediate capture and execution. Unwilling to believe him capable of such a crime, Ichigo, Rangiku, Rukia, and Renji set out to find Toushirou.