The Promise

Na-Yeon (Lee Yu-Ri) is a bright woman. She supports her boyfriend Tae-Joon (Seo Jun-Young), who is from a poor background, and has even given up entering a university. But Tae-Joon dumps her for his success and goes with Se-Jin (Park Ha-Na), who is a granddaughter of Baekdoo Company president.
Do-Hee (Lee Yu-Ri) is Na-Yeon’s twin sister. She is arrogant and tough. Do-Hee works as a reporter at a weekly magazine. After Na-Yeon’s death, Do-Hee decides to take revenge. She takes on the identity of her sister Na-Yeon. Do-Hee then meets Hwi-Kyung (Song Jong-Ho), who is successor of Baekdoo Company.