The film is an alternate story to the Fate/Stay Night TV series. Many things are the same. There is a Grail War, a battle amongst people who are Magi. They must fight and defeat each other until only one remains. The characters are the same people but there are many major differences. First, there are seven Magi instead of twelve. Second, while Shiro is still a main character, Saber is stowed away to the background except for some key battle scenes. Rin instead takes the lead and serves as the main love interest. From there, the story diverges a great deal while keeping certain points the same.