Throughout middle school, Ayumu Kamei and Runa Takishima engaged in a constant rivalry, with Ayumu, though older, consistently falling victim to Runa's pranks and teasing. As they enter high school, Ayumu is determined to earn Runa's respect. However, she soon realizes that Runa's charm and wit continue to outsmart her at every turn. Despite her efforts to outmaneuver him, Ayumu finds herself unwittingly drawn to his schemes, oblivious to his true feelings. To emerge victorious, she must uncover Runa's weakness, only to discover that it lies in her own vulnerability to him.