Ten years ago, Bai Lan's (Song Jia) daughter Ling Dang was kidnapped and died accidentally. The serious crime squad police officer Chen Hao (Wang Qianyuan) promised the child's mother that he would bring the murderer to justice. After a long investigation, Chen Hao found nothing and left the police force with regret. Ten years later, Chen Hao accidentally discovered new clues. Bai Lan, who was terminally ill, regained hope and decided to find the murderer for her daughter. The two began to investigate and found clues left by the criminal. At the same time, Li Aijun's (Feng Yuanzheng) granddaughter was also kidnapped. The kidnapping method was exactly the same as 10 years ago. Facing the cunning suspect, can Chen Hao and Bai Lan catch the murderer and fulfill their long-cherished wish...