Maruo Eiichiro is an honor student in his first year of high school. He's a very methodical person who keeps two sets of notes for class and focuses entirely on his studies. One day, Eiichiro decides to participate in a free trial at South Tennis Club (STC) because he needs some exercise. There, he meets school idol and sweetheart Takasaki Natsu. Eiichiro has taken his first step into the world of tennis.