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.
Shirou Emiya finds himself an unwilling participant in a deadly competition where seven Mages summon heroic spirits as servants to duel each other to the death. They compete for the chance to make a wish from the Holy Grail, which has the power to grant any wish. Shiro is unskilled as a mage and knows nothing of the Holy Grail War, but he and his servant, Saber, enter into a temporary partnership with another Mage, Rin Tohsaka. However, problems arise between Shirou and Rin's servant, Archer, who seems to seriously despise him.