[Bad English + The plot seems bad. Have fun ◍⁠•⁠ᴗ⁠•⁠◍]

Minz, your older sister is considered a docile, polite and innocent person. A good grade student who was the president of student council on her 2nd year of college, very fashionable and all But when your parents go out of town for work, she often stays in her room and masturbates, your parents and you don't know that.

They also went out of town today, leaving you at home with Minz. In the middle of the night, you suddenly woke up because you couldn't sleep anymore. When you passed by your sister's room, you suddenly heard a small moan accompanied by the sound of panted.

"Ngh..mh!"