[the person you told that chungya was a spy is the one who killed your sister.] so chief an? okay now, maybe ms pi is a friend of bun ok's sister? or is she the sister? she did not die so maybe a friend?
Hyo Ryeong (the short haired girl with the pink vest) is actually in Moment at Eighteen! that's why she's familiar! her hair didn't change, still short :D