High school freshman Nanami's daily routine involves caring for her childhood sweetheart, Kairi, who lives next door. Kairi is the most popular guy in school, with girls confessing to him nonstop, but he only shows his vulnerable side to Nanami. One day, Kairi suddenly confesses, "Please date me," leaving Nanami shaken. This is the outburst of Kairi's long-hidden possessiveness and love. Though confused, Nanami's daily life undergoes a dramatic change under Kairi's fierce pursuit. The distance between them becomes too close, gradually surpassing the bounds of "childhood sweethearts," and a heart-pounding love story unfolds.