The story behind the "Heart Attack" MV based on seoljeong couple. Foreword— Uhm.. Are you new here ? i have never seen you.. — I am, i just moved in today, i live on 7th floor ! the girl said still smiling.— I see, that was you all the noise and everything ! I live on 6th floor. Hyejeong said, smiling afterwards, realising she could have been offended with the way she had said it.— Yeh, that was me… The two girls stayed silent for a while.— Do you want a donut ? Hyejeong asked non chalantly, handing the bag full of donuts to the girl.— Sure,i’m starving ! the girl said, taking a pink icing donut. I’m Seolhyun by the way ! the girl said with an angelic smile.— Hyejeong.  the other replied. 6th floor, i should go now. see you someday !  Hyejeong said while walking through the elevator’s door. Seolhyun replied with a cute « See you ! » before the doors closed.