For twenty-eight years, Yoo Hee-yeol has been active as a musician. He also was a late night radio DJ and currently works as a broadcaster. Starting with the radio program, "Yoo Hee-yeol’s FM Music City" of the late nineties to the T.V. music talk show, "Yoo Hee-yeol’s Sketchbook," he has been the nocturnal MC. He was recently persuaded by the production team to appear in "Let's Take a Walk at Night" on Kakao TV program and explored all corners of Seoul for four months, putting to use his typically astute observation and specialized nocturnal sensitivity gained from his long experience as a nighttime DJ. He has always enjoyed strolling at night but as he took a walk on the many routes that the team had picked out for him, he was able to see much beauty that the city of Seoul had to offer, of which he didn't know about.