The one who obtains the Holy Grail will have any wish come true.

The Holy Grail War.
A great ritual that materializes the greatest holy artifact, the Holy Grail.
There are two conditions to participate in this ritual.
To be a magus, and to be a "Master" chosen by the Holy Grail.
(The experience as a magus is not questioned if one has the aptitude)

There are seven chosen Masters, and seven classes of Servants.

There is only one Holy Grail.
If you wish for a miracle.
Prove that you are the strongest with your powers.