Unknown Seoul

Twin sisters Yoo Mi Ji and Yoo Mi Rae are are different in everything except their faces. Yoo Mi Ji the younger of the twins, has ended her short heyday as a promising track and field athlete and is currently living a free-spirited life. On the other hand, the older sister of the twins, Yoo Mi Rae, has been walking the path of the elite since her school days and is currently a perfectionist working at a public corporation. The twins, who are physically identical but lead starkly different lives, embark on a bold charade, switching lives for some undisclosed reason.
Lee Ho Su a lawyer at a large law firm with a tall appearance and a seemingly carefree attitude. He may look like a noble swan with no flaws on the outside, but he actually works harder than others to live an ordinary life. This is because he has been living a different life than before after experiencing something in the past. As a result, he lives a calm life without showing his true feelings, but one day, an unexpected encounter occurs that sends waves through Ho Su's heart.
(source : mydramalist)