The story of how I spoiled my cute little sister so much in my imagination that it came back to haunt me when it was discovered.

I, Seto Ayane, am what the world calls a "NEET girl." One day, while I pressed my ear against the wall of my sister's room to check on her safety, I heard a strange voice. So, to ensure my sister's safety, I inspected her room while she was away and ended up finding it‼︎ Because of that discovery, the relationship between my sister and me accelerates more and more.