Aihara Kotoko is a lagging Class F student at the High School Annex of Tonan University, who has a crush on Irie Naoki, an outstanding Class A student rumored to have 200 IQ. She decides to profess her love to him, and hands him a love letter. But he rejects her outright with a simple "No thanks." Kotoko with a wounded heart moves to a new home with her father, but the house gets destroyed by a meteorite. Because they have nowhere to go, she moves in with her father to his best friend's home.  However ...
Onii-chan's a little odd though, isn't he?
Onii-chan es algo extraño, la verdad, ¿no?
Aunque es un poco rarito, ¿no crees?
Mon fils est un peu bizarre,
mais essaie de bien t’entendre avec lui.
Mas meu filho é um pouco 
estranho, não acha?