Gugudan's Haebin is the voice behind "Since Then" for part 5 of the 'Children of Nobody' OST. 

In the music video for the MBC drama series above, Cha Woo Kyung (played by Kim Sun Ah) does her best to uncover a mystery. "Since Then" is about being unable to escape a darkness in your life. Listen to Haebin's "Since Then" above!