Tsukasa is an ordinary teenage boy, whose best friend Satoshi receives a mystical wish-granting idol from his uncle one day. Satoshi, ever the pervert, wishes for a cute, tiny, and perverted childhood friend with huge tits to become his lover. Suddenly, everything around Tsukasa becomes dark…

When Tsukasa wakes up, he finds himself six years in the past. Moreover, he finds that reality has changed so that, instead of being born a boy, he was instead born a girl. Tsukasa puts two and two together and realizes that the idol intended to grant Satoshi's wish by turning Tsukasa into his ideal type of woman. Realizing that history will repeat and Satoshi will get the wish-granting idol in six years, Tsukasa strives to retain his sense of self and avoid becoming his best friend's girlfriend.

Included in the genderswap collection TSF no F no Hon Sono 4 (TSFのFのほん その4).