「I aspire to be a villainess."

A girl named Sanae Oonishi, from my literature club, declared this.

At the time, I thought she was just joking and laughed in response.

But the next day, for some reason, a villainess was standing in front of the anus, looking for me. She told me she'd woken up in Sanae Oonishi's bed that morning.

What is this? Sanae Oonishi has completely become a villainess.