Heard that Hyun Joong had a business meeting yesterday when he arrived Seoul. It has probably something to do with his new drama.
Here's an article from jbarky of Soompi telling us something about 'City Conques't.
[News] Kim Hyun Joong to Attend Action School to Prepare for Upcoming Drama “City Conquest”
jbarky / Soompi News
Kim Hyun Joong is busy preparing for his upcoming drama “City