The Peach Girl series follows Momo Adachi's high school journey, where she is often dubbed a promiscuous beachgoer due to her tanned skin. In reality, her tan comes from her time on the swim team. Momo harbors feelings for Toji, who supposedly prefers girls with lighter skin. This leads to Momo questioning her identity and confidence. She strives to change herself to become Toji's ideal girlfriend, but her attempts are futile as her frenemy Sae tirelessly schemes against her relationship. Sae takes extreme measures to intervene in Momo's life, even trying to take Toji away from her. Meanwhile, Kairi secretly nurtures his love for Momo.