Why Don't You Make the Twins Your "Girlfriend" Together?

Usami is a beautiful classmate with good morals and top grades. At school, she views Sakuto as her rival. But when he bumps into her after school, he sees a different side of her. She was playing at an arcade after classes, and she had this innocent smile that one couldn't imagine on her at school. For the sake of getting along with her, he gets close to her at school and then plays together with her after school. They each have their places where they can deepen their bonds, and at last...