Tsuchima Taihei and Tsuchima Umaru enjoy an ordinary, happy sibling life.
But lately, Umaru has started acting strange.
Not only does she call herself "this concubine" all the time, her gaming tastes have gotten more and more extreme. She's started openly playing adult games, and now she's even rebelling against her brother!!!
So!
The upright Tsuchima Taihei, who is absolutely not a siscon, decides to have a "friendly" heart-to-heart with his little sister on a dark and stormy night.
P.S. I suddenly felt inspired to write this after watching a certain video on Bilibili.
