High school student Sakuto Takayashiki finds himself in an unusual romantic predicament involving the Usami twins. He is acquainted with Chikage Usami, a beautiful classmate who maintains perfect grades and a model demeanor. At school, she regards Sakuto as her academic rival, but after classes end, he discovers a hidden side to her personality. He encounters her playing at an arcade, where she wears an innocent smile completely different from her disciplined school image.

As Sakuto spends more time with Chikage both during and after school, their bond deepens. One day after school, she confesses her feelings to him, and he accepts. However, just as they begin their relationship, another girl identical to Chikage appears, insisting that she was the one who confessed. The truth emerges that the girl Sakuto knows is actually two people: Chikage Usami and her elder twin sister Hikari Usami. Both twins have independently developed feelings for him, leading to a double confession.

Rather than forcing Sakuto to choose between them, the sisters propose an unconventional solution. He begins dating both Chikage and Hikari simultaneously, following their suggestion. Their days become filled with alternating solo dates and moments when all three spend time together. The story follows this warmhearted romantic comedy as Sakuto navigates relationships with two very different girls who share the same face. The setting centers on their high school and the local arcade where the twins reveal their genuine, carefree personalities away from academic pressures.