Fifteen years ago, the sisters of the Lu family witnessed their father being murdered at home, but luckily they escaped the same fate. Their father's death was disguised as suicide by his business partner Zhao Wen Dong, who became the owner of the company. The two sisters vow to find out the truth and avenge their father. Not wanting to put her younger sister Lu Xi in danger, the older sister Lu Si decides to investigate on her own, but she has no idea that Lu Xi is already involved in the case. The two sisters gradually approach the truth from different directions of investigation, and, at the same time, their emotional lives also face great challenges...