Ga-Ram is an inspiring K-pop idol. As her name begins to get out there, one of her favorite K-pop groups, Stray Kids, reaches out to her and asks if she wants to open up for them on their tour. Taking the opportunity, she packs her bags and goes with them. Being the youngest, they all look after her. But what happens when some of them start to show feelings towards her?

Changbin has been best friends with Jisung since their days as trainees. One day, Changbin walks into Jisung's house and sees a girl who looks like him, but he doesn't know who she is. She has long black hair and brown eyes. It turns out that it's Hae, Jisung's younger sister by five years years. She's home for the summer from university, and Changbin begins to develop feelings for her as she spends more time with him and Jisung. But with Jisung being the protective brother that he is, can they start a relationship?