From Rooftop Love BL:

Ivan, Lieutenant and spy in the service of the Russian army, must investigate the right arm of a mafia boss. But his target is a very close friend he made in the military academy and who he hasn't seen in ten years, Edward. Ivan can't help but wonder, how could such a compassionate man with a passion for art, become a part of the mafia? When they meet again, Edward seems to be as nice to Ivan as in the past and Ivan, facing a dilemma in his mission, is invited back to his home. But, the next day Edward's attitude completely changes and Ivan realizes that he's been kidnapped!

Dive into the frigid depth of Russia, in the heart of St. Petersburg, and discover the exciting story of two men who oppose each other! Will friendship and love be enough to overthrow fate and bring two ruthless enemies together again?

Official Korean Translation