Seven years ago, the real murderer of the Rainy Night serial case escaped, and detective Chen Su resigned unjustly. Ten years later, he returned to the scene of the crime and found a fingerprint that had been ignored in the old abandoned building - exactly the same as a fresh fingerprint on the account book of the flower shop of Zhou Wenli, the deceased victim's contact. Chen Su teamed up with current captain Zhao Yiming to restart the investigation, but was secretly obstructed by forensic doctor Li Tong. It was also discovered that the real murderer's gloves had appeared in the personal belongings of retired detective Wang Jianguo. When Zhang Hai took out the cigarette butt of the real murderer, all the clues pointed to an unexpected person - Chen Su's most trusted partner, Zhao Yiming.
