Beach for summer vacation. The sandy beach is full of big sisters with big boobs. She is all beautiful and her swimsuit is very naughty ... "Oh ... if my sisters do something like that ..." It's because I was mischievous in my pants by a duo of lewd girls on the train. Because of that, I've been horny all the time ... When I got lost, I happened to peek at the parking lot until my sisters changed their clothes. I knew it was really cool, but it was so naughty that I couldn't take my eyes off it. Of course I found it ... "Come on because it's not terrible ... Do you take off your pants?" She is caught by her older sisters, and her boobs, dicks, and chin are made into toys. I couldn't forget that experience, and I came to the beach day after day, Every time I met lewd older sisters and was mischievous ... After all, the older sisters at the beach are all naughty people! The protagonist is a difficult-aged virgin who is a little tsundere to her classmates of the opposite sex. Although she is lewd like a boy, she has little immunity to naughty things, She becomes obedient and docile as soon as she has her boobs in front of her. She is a gentle and obedient child. And soon after her personality of losing her sexual desire was taken in the wrong direction, Her older sister and her classmates just make it a toy.