Rina Uchimura's younger sister came to Tokyo and started living with her, but this sister has an incredibly flexible body from practicing yoga. With a mischievous, devilish charm and an adorable face, her soft, erotic poses captivate everyone who sees her. Tempted by her flexibility, her brother-in-law finally touches her body. Intending to comfort the sister after she's been toyed with and hurt by a city man, their relationship gradually deepens. Soon, the brother-in-law becomes intensely attracted to his young sister-in-law's body, completely enchanted by her softness.