Because of her childhood experiences, first-year high school student Saki Miyanaga dislikes anything connected to mahjong. When she does play, she stays under the radar to avoid drawing attention. One day, her friend Kyoutarou Suga pulls her into the school's mahjong club. There, she encounters Nodoka Haramura, the previous year's national middle school mahjong champion, and Yuuki Kataoka, another club member. During a few practice rounds, Saki tries to conceal her skill. However, club president Hisa Takei spots Saki's distinct style of play. Seeing her potential, Takei tests Saki's true ability—confirming she is more gifted than anticipated. This discovery hurts Nodoka's pride, and their relationship begins on shaky ground. Saki eventually joins the club, and after resolving the misunderstandings between her and Nodoka, a friendship develops between them. As Saki gradually grows more comfortable with mahjong again, she and the rest of the club share a single objective—to win the nationals!