《The Doomsday Knight》 is a Korean science fiction action drama written and directed by Cho Yi-seok, starring Kim Woo-bin, Song Seung-heon, Kang Yoo-suk, and Li Su.The drama is adapted from the webcomic of the same name created by Lee Yoon-gyun. It tells the story of the Korean Peninsula in the future where air pollution is serious and people cannot survive without oxygen. The legendary courier “5-8” and the refugee “April” fight against the Cheonmyeong Group that dominates the new world.story.