I thought it was sang by Dara ~ because some parts sounds like she was the one singing it and I didn’t notice the first 10 seconds of the video where they put who sang it keke ~ Anyone thanks to Chiiyong unnie for correcting me ^.^/
One Step Music Video – Shy Day by Lee Aram and Younghwa (not sure if its CNBlue’s Younghwa)
Credits: 민병석