This drama is about a pure man who accepts a dangerous destiny for the woman he loves. It is a love story that spans over two hundred years. Moon Soo-ho (Kim Rae-won) is a businessman with a pure heart who braves danger for his love Jung Hae-ra (Shin Se-kyung), who is a travel agent but never traveled abroad.
Kim Rae-won as Moon Soo-ho / Lee Myung-so (Black Knight)
Sung Yoo-bin as young Moon Soo-ho / young Lee Myung-so
He is a successful CEO who is strict to himself, and he never shows his true colors. But when he is in love, he is a pure romanticist. After the death of his parents, a friend of his father became his guardian and looked after him. He and his guardian's daughter grew up like siblings, and he slowly developed feelings for her. However, the joy did not last long. He felt betrayed and hurt by his guardian and his daughter. When he is on the verge of breaking down from despair, a delivery woman tells him that a big fortune is waiting for him in the future. Her words become a prophecy and he keeps on rolling. The endless luck scares him because he worries that he might have to repay all of it later. Then, he meets the guardian's daughter again. She makes his heart flutter even though she hurt him. She is his first love.
She works for a travel agency. Even though she is poor, she takes care of her aunt and maintains a cheerful attitude. As a child she was pretty well-off. However, when her parents died and her family went bankrupt, her life turned upside down. She did not lose hope because she had a job, a house, and a boyfriend. But misfortunes never come alone. Her work, family and lover drag her to the pit of her life. Then she remembers the wine-colored coat she had ordered at Sharon's Boutique as a child. She never got to pick it up because her family suddenly went bankrupt. Could her life have changed if she had picked up that coat? After she unexpectedly finds the coat, strange things start to happen to her. Then she meets him, the man who calls himself her black knight.
She is the designer at Sharon's Boutique. Although she attracts much attention with her beauty, her personality is selfish, cranky, and egocentric like a child. She keeps a huge secret. She has been living for more than 200 years without getting old or dying. Ever since 'that day', she has been spending lonely days without aging. She is receiving punishment for the sin she committed 200 years ago, but she is so stricken with a victim mentality that she never grows or finds enlightenment. When Hae-ra visits her boutique to find the coat she had ordered as a child, she tries to escape from karma by being generous to Hae-ra. She desperately wants to break away from the endless punishment. But at that moment, she meets him again. The man she has been missing for hundreds of years. The man she believes to be her destiny.
She is a perfumer and cultural heritage commentator of Seochon. A mysterious aura surrounds her entire body. Her other job is a power blogger. She lived for 250 years and writes interesting stories on her blog. No one knows that those stories are her actual experiences. She hopes to break away from the punishment and become mortal again. Then she meets the lovers who are tangled up by a terribly cruel fate. They marked the beginning of her karma.
^2018코리아드라마어워즈 후보 공개. KDFO.org (in Korean). September 22, 2018. Archived from the original on October 6, 2021. Retrieved September 27, 2018.
^Woo, Bin (January 1, 2019). [2018 KBS 연기대상] 유동근 대상 "장미희 덕분인데 내가 왜..대하드라마 부활 기원" [[2018 KBS Drama Awards] Donggeun Lee Grand Prize "Why am I ... thanks to Jang Mi-hee.]. Ten Asia (in Korean). Archived from the original on January 1, 2019. Retrieved January 1, 2019 – via Naver.