A pure and serious older sister figure, Rie Ayamoto, who is engaged and has only ever been with her fiancé, finds herself in an unexpected situation that adds depth to the story. Despite not being a professional talent, her genuine innocence captivates throughout. Curiosity sparks during conversation, leading to a hastily arranged encounter—her second sexual experience with anyone other than her fiancé. Overwhelmed by intense pleasure bringing her to tears, she soon finds herself anticipating a threesome. A mix of humiliation and regret swirls within her as she breaks down, crying at the sight of her own shameful actions. The striking contrast between her modest appearance and inner desires creates a shocking, unforgettable experience from start to finish.