Yuuki Rin is a brilliant student attending a prestigious private university.
If you ignore the fact that she’s an AV actress, she’s just your average college girl.
Even to me, her younger brother, she’s beautiful, kind, and someone I’m proud to call my sister.
But one day, she dropped a bombshell.

“I’m dating our cousin, Micchan, with marriage in mind. So, don’t you dare tell him I’m doing AV, okay?”

My sister and our cousin were head over heels for each other.
Honestly, out of all the couples I’d seen in recent years, theirs was the most infuriating.

“Hey! You’re not planning to peek, are you?! I’ll give you some allowance, so go out for a bit!”

And then, through the wall, I could hear the creaking bed and their moans.
Meanwhile, on the monitor, there was my sister, getting pounded by an AV actor and moaning like crazy.
This is the sad story of a younger brother whose AV actress sister started dating someone wanting to marry.

[Translated from dlsite]