In the near future, humanity faces imminent destruction from mysterious creatures known as "Huge." The world wages war against the Huge, and develops the anti-weapon "CHARM" (Counter Huge Arms) by combining science and magic.CHARM works more effectively when used by teenage girls, and those who use the weapons are revered as "Lilies."
The story of the card game follows what happens when "Hairou" portals suddenly open, fusing five different worlds together. As a result, various mysterious "Exceed" powers are awakened in teenaged girls. An academy for these so-called "Progress" girls is built on the isolated Seiran Island in the Pacific.
Kimito Kagurazaka is an ordinary high school boy who is kidnapped by an elite young lady's academy to be a "sample of the common people." The school is full of sheltered girls who have never met male peers before.