Rin, my cousin who moved to Tokyo five years ago due to her parents' work, will be staying at her relative Yuzuru's house for a week this summer. Yuzuru is two years older than Rin and has been like an older brother to her. They used to play together catching bugs when they were little. Even Yuzuru's parents were out working part-time, and Rin, whom he hadn't seen in a while, had grown up. Rin, whom Yuzuru still thought of as a child, had a cute face and breasts that had developed impossibly. Yuzuru, who was always masturbating, saw Rin naked in the bath and couldn't control his erection.
