Rise Okitsu is a new student at the very prestigious Jyoshioka Gakuen Private High School, which was formally an all girls school. When the story starts out, she's in the commoner class, though at the top of her class. She ends up hiding in a closet and there Azusa Mizutani finds her when he himself is trying to hide from all the crazed girls chasing him from the S-Class; the richest of the rich class. To make the girls go away, Mizutani makes a split second decision and pledges himself to Rise so that the girls back off, and suddenly she's the pretend girlfriend of a very attractive and sought after guy. With this though comes lots of bullying from the other female students, and it's hinted that something like this has happened before in middle school. After constant bullying, Rise is transferred to the S-Class by Munechika, a disciplinary committee member whom has ties to people in high places, and is also another rare male student.
Okitsu is usually seen as a quiet girl, but with Mizutani and some of the other guys, her true colors come out and it's seen that she is easily flustered and becomes violent when upset, often times abusing Mizutani.