Dalkomhan Insaeng (2005)

An elegant sky lounge floating like an island in the sky above Seoul, it's like Sun Woo's own little castle. After 7 years he has climbed to the top, managing the upscale lounge and restaurant. An intelligent, cool-headed perfectionist, Sun Woo has earned the absolute trust of his boss with his undivided loyalty and by adeptly managing the business. His boss, Mr. Kang, is a callous man with a secret--his young love, Hee-soo. When Mr. Kang suspects Hee-soo might have another boyfriend, he orders Sun-woo to keep a close eye on her and to kill her if she has betrayed him. After following her for a few days, Sun-woo barges in on Hee-soo and her boyfriend with a clear mission--but to his own surprise, he lets them go. Sun-woo hopes everything will just go back to the way they were. But his decision has launched an irreversible war with the whole gang, guys who were like brothers just the day before.