It is the start of a new year in the sixth grade of elementary school. The girls and boys don't get along very well together and the boys often play pranks on the girls such as flipping skirts to see their panties.
In this childish world a new transfer student arrives. The boys want a new boy to join their clubs and play sports with. The girls want a new girl to enjoy chatting with and having fun after school.
The new arrival is Kasuga Hikaru a high class girl with drill hair. She shocks the class during her introduction by yelling out "I hate you all!"
Though Hikaru is quite the loner Katsuragi Yuna still tries her best to become her friend. After much effort Hikaru finally gives in. She decides to make the "After School Nyan Nyan Club" and she recruits one of the boys in class Konoe Satoshi so the three can explore the adult world together . . .