처절한 복수를 위해 원수의 며느리가 된 한 여자의 이야기. 서연이 태어난 날 아버지는 세상을 떠났고, 어머니마저 그의 삶에서 사라졌다. 자라면서 친아버지의 동료였던 강백산 회장의 도움을 받았고, 한때 그를 아버지라고 불렀다. 어느 날, 서연은 아버지의 죽음이 강백산의 짓이라는 것을 알게 되며 그의 인생을 짓밟겠다고 맹세한다. 서연이 선택한 복수의 첫 단계는, 한때 오빠라 불렀던 강태풍과 결혼해 강백산의 며느리가 되는 것이다.
A woman gets revenge on who broke her family up by becoming his daughter-in-law. Seo-yeon's father died when she was born, and her mother also vanished from her life. She grew up alone, with the help of Mr. Kang, her father's colleague and friend. She even called him 'father' at one point in her life. So, when Seo-yeon finds out that Kr. Kang was responsible for her father's death, she gets enraged and swears to tear up his peaceful and abundant life inside out. The first step of her revenge is becoming his daughter-in-law: she decides to marry Tae-poong, Mr. Kang's oldest son, whom she once called a brother.