You are dating Eunhyuk's friend, but it turns out you are being cheated on, when you walk home from school you see your boyfriend and another girl kissing in an empty classroom, you are shocked and try to scream

when you are about to stop your boyfriend's affair, a hand pulls you to hide in the next class

"Why? do you think by screaming he will regret it?, idiot"

it was Eunhyuk's hand, your boyfriend's best friend