I'm so kind that I don't have any friends (I don't have any friends because I'm kind).
The female protagonist, Oh Yu-jeong, is a timid final boss who is kinder than the average person and can't even say no. So she becomes a high school student and is a pushover for some female students. She can't say anything when she's being bullied by other students and just listens to everything. Her classmates also just watch. But suddenly, a transfer student comes to the female protagonist's class!