From the video:
Three North Koreans spies attempt to live in South Korea as ordinary men. The men are characterized as a stupid man, a wanna be idol singer and a high school student. After two years, they receive an order from North Korea…
Based on webcomic “Covertness”.
Other than Kim Soo Hyun, it stars Park Ki Woong, Lee Hyun Woo and Son Hyun Joo. Help, I have a thing for Park Ki Woong, even with the orange hair! Secretly, Greatly hits theatres on June 5th.
Credit to the uploader and Daum.