Mm. Yeah, that's pretty much it. But specifically, what it does is have the ability to grant any wish a person desires. There's, of course, the original holy relic that contained the blood of Christ, but there are also artifacts that draw upon that original's power, and have immense magical power themselves. They appear very rarely from time to time, usually through rituals or circumstances that allow them to exist.

[A shake of the head.]

So, you have an artifact like that, and a bunch of mage families who will kill and murder to get any kind of power, so what do you think happens? A full-on war, of course. That's what's happening in Snowfield, Nevada. A Holy Grail War, and the poor inhabitants of that city are none the wiser as to the kind of devastation that it will bring.