Sensei Kunshu. Samaru, Ayu is a girl who feels that she hasn't got any luck in love because she was always rejected.
One day, a cute boy comes to rescue her when she doesn't have enough money to pay the bill in a restaurant. Ayu feels really excited about this incident, but she finds out the day after that the beautiful boy is actually her new math teacher, Hiromitsu, and he's treating her badly...? What will happen in between these two? Real lessons are going to start from Ayu!