This is the story of Ai, an introverted girl whose fate is forever changed when she acquires a mysterious “Wonder Egg” from a deserted arcade. That night, her dreams blend into reality, and as other girls obtain their own Wonder Eggs, Ai discovers new friends—and the magic within herself.
On the way home from school one day, Konoha Koga rescues Satoko Kusagakure, a ninja who escaped her village. Soon, pursuers from the village show up in search of Satoko only to be deftly dealt with by Konoha. As it turns out, the unassuming high schooler is actually an assassin. Thus, the potentially cutthroat cohabitation of a ninja and an assassin begins!