Yuna never wears a bra at home. Her father, seeing her like this every day, has recently begun struggling with conflicted feelings. Though she's his daughter, it's awkward and increasingly difficult to ignore the inappropriate thoughts that cross his mind. The more he tries to suppress them, the stronger they become. Meanwhile, the private tutor who comes to teach Yuna is also growing uneasy. During lessons, he feels she unconsciously tempts him with her immature yet alluring body, stirring emotions he can't control. She attends lessons without underwear, wearing a bold, defiant smile that unsettles him. Drawing closer until their breaths mingle, she teases him with mischievous, devilish charm. Drawn deeper into her allure, their relationship gradually escalates into forbidden intimacy.