Kurokiya Ruu is on the verge of repeating a year so her childhood friend Tadashi Tadao steps up to teach her. However, they end up not getting any studying done as she uses this situation to try and seduce him at every turn.
This was boring. The story focuses on a boy and a girl. When the two were children, the girl was much better at studying than the boy. Years go by, the two meet again. Now the girl becomes a gyaru, who is so bad at studying, that she might even repeat a year. She meets her past friend, who is now supposed to help her avoid that, but instead of this, she tries to seduce him like a slut she is. Honestly, there are 10000 stories like that.