My Golden Life (황금빛 내 인생)

25 years ago, Haesung group lost their granddaughter Choi Eun Seok (Seo Eun Soo). The girl was found and raised by Seo Tae Soo (Chun Ho Jin) as one of his twin daughters Seo Ji Ahn (Shin Hye Sun) and Seo Ji Soo, They grew up rich but their father bankrupted and they had to experience the hard life of poverty. Ji Ahn now is a contract worker at Haesung group who would do anything for a job while Ji Soo is an airheaded part-timer who has a one-sided crush on Sun Woo Hyuk (Lee Tae Hwan), Unknown to her that Woo Hyuk was in love with Ji Ahn in high school. Choi Do Kyung is Haesung Group oldest grandson, he is gentle and kind but being too good yet still single makes his employees spread weird rumors about him, he meets Ji Ahn in a car accident and comes to know her sad situation but his biggest shock is when his mother reveals that his lost sister is Ji Ahn.

(Source: MyDramaList)