Fate/stay night

Emiya Shirou is a highschool boy who lives in Fuyuki City. His parents died in a fire when he was young, after that he was adopted by an old man who refer himself as a sorcerer, but he died too.

What Shirou doesn`t knew, is that the underground of Fuyuki City is the place of a great war.

When the time is right, sorcerers from near and far gather with their Servants - the summoned spirits of heroes so mighty they exist outside of time - and fight a war for possession of the Holy Grail, a relic said to grant its owner a wish. The true names of the Servants reveal their weaknesses, and so they are usually referred to by a classification of type instead; Saber, Archer, Rider, Berserker, Lancer, Caster, and Assassin.

One day, Shirou saw a fight between two servants, Archer and Lancer.

To preserve the secrecy of the war, Lancer mortally wounds him; but a girl who up until now seemed a normal classmate of his, Tōsaka Rin, saves his life using a magical pendant.

On his way home, Lancer attacked him again. Just before he`s about to die for good, the servant Saber appears before him, greeting him with the words "Are you my master?"

Taken from AniDB