If someone looking for more story he should buy the game Fate/hollow Ataraxia. Then you can have a little different view on this anime.
. I liked so much Fate Stay Night that I started doing game about it, and it has something fimiliar with it like heroes.
You can summon them but it dosnt matter from what time they were living ;-) just like in Fate for examples are Berserk (he lived past) and Archer (who lived in future).