After transferring into an elementary school in Nara, Nodoka makes friends with Shizuno Takakamo and Ako Atarashi. Upon hearing about her interest in mahjong, they take Nodoka to Achiga Girl's Academy, where Harue Akado runs a mahjong club for children. After a few games with Kuro Matsumi, Shizuno later tells Nodoka about Harue's history, including reasons leading to Achiga's club disbanding. By the year's end, Harue accepts an offer to join a company's mahjong team, which leads to the closure of the children's club...