Fujimino Girls' School's system – the “Aikata System” – is a system in which students who are most compatible with each other are paired up for a year to share their school life together. The students share their problems and joys with their chosen partners and build a deep bond with them.

The partner of Nao, a serious first-year student, is Ibuki, a popular second-year student. Nao can't keep her heart from pounding every day, but some other students don't like their relationship... On the other hand, Nao's partner in the same class is a beautiful and mysterious second-year named Yuka. The connections between the girls are constantly being pushed around, but there is a hidden reason behind Yuka's attitude…

The school drama spun by their intersecting feelings now begins!