The Promise.

Na-Yeon is a bright woman. She supports her boyfriend Tae-Joon, 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, who is a granddaughter of Baekdoo Company president. Do-Hee 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, who is successor of Baekdoo Company.