Sora-tan is a girl with a dark personality who gets teased by everyone at school because she's always at the edge of the classroom. But what people don't know is that she's actually the most mature one among them all. Today, after school ends, she's learning some naughty stuff from her older man. She seems really into it and even wants to be his secret lover until Mama comes back home later tonight.

そらたんは、暗い性格だと学校のみんなに笑われるクラスの端っこにいる存在。だけど、1番大人なことをしているのはそらたんなんだ。今日も学校を終えるとおじさんにちょっぴりHな事を教えてもらってるんです。生でするえっちなコトにハマっちゃったそらたんは、今日もママが帰ってくる前までおじさんのセフレ？ってヤツをやっちゃうみたいなんです。