I'm visiting my grandmother's house for the first time in a long time. I thought I was going to spend a gloomy time surrounded by relatives, until I met that girl. She lives with her mother and is three years younger than me. In my memory, she was still in elementary school, but now she has grown into a woman with smooth skin and breasts that look like they might burst out of her uniform... My cousin is in her adolescence and is curious about sex, so we spend our summer vacation together, a secret that we can't tell our parents about.