The OST is sung by Eric Nam, who lends his beautiful voice to the drama for an amazingly emotional song. The MV to the song features scenes from the first few episodes of the drama and shows the tragic past of the two main characters Kim Min Joon (played by Woo Do Hwan) and Choi Kang Woo (played by Yoo Ji Tae).

SEE ALSO: Eric Nam gives hints to lyrics to his comeback song 'Miss You'

Check out the song above. Are you watching the drama?