Tomoko Kawasaki
Ryou Mizuhara is a normal high school student, living alone with his younger sister Akane. They were very happy together, at least until a mysterious girl crashes into their lives who introduces herself as Ryou's new fiancée.
Earth. The not too distant future. A city is miraculously reborn just sixteen years after being completely destroyed by a giant meteor. At the prestigious Graviton High School for Girls, two new students are introduced. A-ko and her ditzy sidekick, C-ko.