In a Holy Grail War, Mages (Masters) and their Heroic Spirits (Servants) fight for the control of the Holy Grail—an omnipotent wish-granting device said to fulfill any desire. Years have passed since the end of the Fifth Holy Grail War in Japan. Now, signs portend the emergence of a new Holy Grail in the western American city of Snowfield. Sure enough, Masters and Servants begin to gather... A missing Servant class... Impossible Servant summonings... A nation shrouded in secrecy... And a city created as a battleground. In the face of such irregularities, the Holy Grail War is twisted and driven into the depth of madness. Let the curtain rise on a masquerade of humans and heroes, made to dance upon the stage of a false Holy Grail.

The special of the day is Variable Geo-a brutal battle between waitresses who serve up generous portions of energy blasts and vicious side orders of murderous martial artistry. For buffed beauties who make below-minimum wages, VG is the perfect way to make some fast cash. The victorious walk away with millions, and the defeated lose everything (namely, all their clothes). But this high-stakes sport has dark forces and dubious practices behind the fun and games. Lethal injections make steroids seem like vitamins. Instead of team prayer, there's demonic possession. Athletic sponsors are malevolent corporations with a more frightening agenda than increased market share. It's all just part of the game.

Manami is your typical schoolgirl, despite the odd machines her grandfather is always building. One day, though, an odd evil robot comes to attack Minami's school, and commits the ultimate offense of threatening her friends... and ruining her lunch. Now, she will stop at nothing to return order to the world in her grandpa's newest creation: the mecha Del Power X.

Unidentified creatures "Archon" suddenly appear and bring the human beings to a crisis of extinction. A special corps "Goulart Knights" is formed to counter attack Archon. The knights have supernatural power to generate "Holy Grail" from their spirits and battle against Archon.