Prequel to Fate/Prototype.

Sato Yu is a 12-year-old boy. He is a deprived person. His life is depriving. His step father has a large amount of debt. One day, he is transported into a different world with cheat like stealing ability. Will he stay deprived?

From Baka-Tsuki:War of the Holy Grail - Pursuing the power of the "Holy Grail" which grants a miracle, this is a contest in which seven magi summon seven Heroic Spirits to compete for it. In that battle whose conclusion was postponed three times, now, the