Fate/stay night

Ten years ago in Fuyuki City, a young boy was caught in a massive inferno that incinerated his parents and consumed a large portion of the city; as he was dying, a man saves him. Now this boy, Shirou Emiya, is an amateur mechanic who attends school at Homurabara Gakuen. Shirou also seems to be quite a bit of a magician but his abilities are no where near the level of his late father's. Meanwhile, the city is beginning to be plagued by gas spills and homicides and with Shirou's sense of justice starts to kick in, what could someone like him possibly do?