Suugaku Joshi Gakuen

Kazuki Sato (Dori Sakurada), a hater of math, is transferred to a new school. On the first day of his new school, he walks to school and spots a pretty girl named Nina Machida (Reina Tanaka). At school, his homeroom teacher takes him to a classroom. On the chalkboard is mathematical formulas. He is surprised. His homeroom teacher tells him that his new school specializes in mathematics. Kazuki Sato is stunned.
On the other hand, Kazuki Sato is happy to see many pretty girls in his new classroom. When he sits in his seat, he sees a girl climb through the window and into the classroom. The girl sits next to Kazuki Sato. The girl turns out to be Nina Machida, whom Kazuki spotted on his way to school.
During break, Nina Machida takes Kazuki School to the school cafeteria and tells him to buy bread whenever she asks. At this moment, Sayuri Tachikawa (Sayumi Michishige) and her two friends, who do not like Nina Machida, scheme to get Kazuki Sato and Nina Machida expelled from school.
Kazuki Sato walks around the school and sees a bunch of girls recite mathematical figures. He wonders to himself what they are doing. A girl then comes close to him and tells him that they are practicing to become the math president. Meanwhile, Nina Machida sits on a bench and a teacher sits next to her. Nina Machida tells her that she misses her older sister a lot. Her older sister went missing, right after she became the math president. Now, Nina Machida wants to become the math president ...