A hundred years after an asteroid strikes the Earth and leaves the next few generations with special powers, the world’s most advanced city has been founded to settle fights between the academies in the city of Rikka, more commonly called Asterisk, for control of whatever the winner of the yearly competition wants. In the fights, one or more combatants must face off against an equal opposite number of combatants and uses their Genestella powers plus a chosen weapon (called a Lux) to defeat, incapacitate or make an opponent yield. The fight is watched by a crowd and once the challenge to fight is issued, cannot be rescinded. Into this comes Ayato Amagiri who joins one of the academies in search of his older sister who vanished a while earlier after going to the same academy. Within the first day, he sees a girl in a state of undress, proves himself a hero and gets hit on by his student year head. He hasn’t even gotten to the second day yet.