Thirty minutes later, Gyeong-su realizes he doesn't know why Na-yeon is in detention. So he asks her.
"Why are you here?"
As predicted, Na-yeon ignores him. Now, she's busy wiping Ms. Park's desk, a desk Gyeong-su wiped four hours earlier.
"I wiped that already," Gyeong-su points out. "Why don't you scrub the windows? I haven't gotten to those yet."
But Na-yeon, once again, ignores him. What Gyeong-su doesn't know is that she didn't do anything at all to end up in detention-Ms. Park put her up to it.
---
When Gyeong-su ends up stuck in detention with his arch-nemesis, Lee Na-yeon, he decides he must make the best of it so he can quickly leave and go home.