Basically, this video is about magicians who fight against each other in something called the Holy Grail War. Magicians summon servants that fight for the magicians until only 1 magician and servant pair are left and they win the Holy Grail. The Holy Grail, grants any wish that the winner may have. Well...have fun. This anime was based on the game Fate/Stay Night(Lolz). http://en.wikipedia.org/wiki/Fate/Stay_Night