Seven Seas Nanami, my adorable little sister, has recently started cosplaying. She's shy about showing off her costumes but she agrees to do so if it means pleasing her big brother. As we begin our photo shoot using his smartphone, he can't help but take lewd photos of her, making her pose suggestively while he rubs himself through his pants. Despite feeling awkward, she goes along with whatever he wants. Soon enough, their innocent photo session turns into something much more explicit; his cock ends up in her mouth, and she finds herself being violated by her own inexperienced pussy. It seems that everyone involved has become too focused on their desires, losing sight of what's appropriate.

人前に出るのは恥ずかしいけど、大好きなお兄ちゃんとなら最近始めたコスプレの衣装を着てテンションをあげる可愛い妹の七海ちゃん。お兄ちゃんのスマホで撮影会が始まりますが、もとよりお兄ちゃんは七海ちゃんのエッチな写真を撮る気マンマンで撮影しながら股間を膨らませます。‘ちょっとおかしいな？’と思いながらもお兄ちゃんの言う通りにポーズをきめる七海ちゃん。次第にスケベな撮影会になっちゃってお兄ちゃんのチ●ポを口に捻じ込まれたり、経験薄のマ●コに生姦されたりと、肉オナホに成り果ててしまうのでした。