Mahiro Ichiki, the fiancee of Yuzuru, the eldest son of a 150-year-old kimono shop. To marry into this prestigious family, she must gain the approval of his strict father. Mahiro, with her beauty, health, and purity, seems like the ideal bride... But she actually has a secret: she's the legendary "Rika-chan," a top-rated sex worker for two consecutive years. This must never be revealed. She emphasizes her chastity and refrains from sex until marriage, teasing him to the brink... However, the battle-hardened Rika-chan (Mahiro) unwittingly displays her incredible skills. Yuzuru begins to suspect Mahiro. Meanwhile, her father hires a private investigator to look into her background... What will he do?