Years ago, the Achiga Girls' Academy triumphed over the formidable Bansei High School in a thrilling mahjong battle, reaching the national team semifinals only to be defeated by the ultimate victor. Subsequently, the mahjong club disbanded. Fast forward six years, where young Shizuno Takakamo, an elementary student, forges a friendship with the new transfer student, Nodoka Haramura. Eventually, both girls enroll in Achiga Girls', but Nodoka departs in their second year. Witnessing Nodoka's rise to fame as the national middle school mahjong champion on TV the following year, Shizuno is inspired to resurrect Achiga's mahjong club.