Saki Miyanaga is a skilled mahjong player, but she hates the game since she would be punished by her family whether she won or lost when she played with them. Upon entering high school, Saki's friend, Kyōtarō Suga, takes her to their school's mahjong club so Saki can be a fourth player. There, she meets Nodoka Haramura, a very skilled mahjong player and previous junior high champion, and Yūki Kataoka, an energetic first-year who is skilled in mahjong though has trouble staying focused. Saki only plays a few hands and leaves shortly after the club president and student council president, Hisa Takei, wakes up. Hisa notices Saki managed to keep her score at zero, a difficult feat. Hisa manages to get Saki to come back the next day to play a couple more games with Nodoka, Yūki, and Mako Someya, a second-year member of the club. Saki shows her skill in mahjong by attaining the zero score in the first game.
Saki ne comprend pas comment elle s'est retrouvée au club de mah-jong, mais c'est ainsi que Nodoka et Saki se rencontrent. Nodoka gagne haut la main, mais elle s'interroge sur le style étrange de Saki et lui demande une autre partie.
訳も分からず麻雀部に連れて行かれ、麻雀を打つことになった咲。そこには小川のほとりで出会った少女、和がいた。結果、対局は和の勝利で終わったが、咲の打ち方に疑問を感じた和は、もう一回打って欲しいと願う。
Saki fue llevado al club de mahjong sin motivo aparente y decidió jugar mahjong. Había una chica, Kazu, a quien conocí a orillas de un arroyo. Como resultado, el juego terminó con una victoria para Kazu, pero Kazu, que se mostró escéptico sobre cómo golpear a Saki, quiere que lo haga de nuevo.
Saki, coinvolta suo malgrado nel club di mahjong della sua nuova scuola, incontra Nodoka che colpita dal suo strano stile la invita ad un'altra partita.
