At Shiomi Academy, there's a popular myth about "The Shepherd" who allegedly pops up before diligent pupils to grant their wishes. While Kyoutarou Kakei, the Library Club's unofficial leader, engrosses himself in a book at the prestigious Great Library, he receives correspondence from the elusive Shepherd warning of a life-altering event. Alarmed, Kyoutarou dashes to a nearby train station where, in a moment of glory, he saves Tsugumi Shirasaki, a schoolmate, from a dangerous accident. Moved by his heroism, Tsugumi hops on board with the Library Club's mission and invites Kyoutarou to participate in her mysterious "Shiomi Happy Project." Together, the newest editions to the club strive to transform their school and unmask the Shepherd's true identity.