Sister Paradise! 2 Volume 1 Secret Virgin Break◆!

Nanase Keiichi is a younger sister who is raised at an age where she lives under one roof with her five younger sisters. Seeing them like this, Keiichi often felt unhealthy. And during the summer vacation, Keiichi's parents go on a trip abroad. Rina thinks that her sloppy, naughty, older brother will become even more vulgar in her absence, and takes a harsh attitude towards Keiichi. However, Rina is secretly masturbating, even though she says she doesn't like sex. And Keiichi, by chance, finds out about this.