Fate/stay night [Unlimited Blade Works]

Tohsaka, family heir and powerful mage, is chosen as a master in the Holy Grail War. After saving her classmate, Shirou Emiya, she realizes that he's also been chosen as a master. But he doesn't know anything about masters, servants and Holy Grail Wars, so she takes him under her wing to teach him about survival and the significance of the Grail--it grants any wish the victorious master desires.