It's the first day of high school. Everyone enters the school for the opening assembly. Park Sae Bom and Hwang Do Yoon end up sitting next to each other in the auditorium. They put their water bottles on the floor, and the bottles accidentally get switched. After the assembly, they go to class. Sae Bom is sitting at her desk when a girl walks in. She is Yoon Ye Rim, and they instantly click and become besties. Sae Bom opens her bag and realizes the bottle isn't hers. She puts it on the desk. She doesn't know it's Do Yoon's bottle yet. That's when Do Yoon notices his bottle on her desk. He walks over. "This is my bottle," he says coldly. He places her bottle on her desk, takes his own, and leaves without another word. Ye Rim immediately starts teasing her: "Wowww... did you drink from his bottle? That is an indirect kiss".