Shota-kun becomes extremely excited when his older sister Nozomi visits under the guise of an insurance sales pitch. Her figure is flawless—standing at 178cm tall with measurements of 93cm (B), 62cm (W), and 92cm (H)—rivaling that of a professional model. As Shota-kun gets closer to her, his mischievous desires grow stronger. He teasingly strokes her large breasts from below while scratching his ear, and their bond deepens when they bathe together. Sensing that Nozomi doesn't mind, he carefully washes even her most intimate areas. Just how far will the older sister let him go? That answer is one of the highlights of this story.