Cheng Tian, who was once a criminal investigation genius in the provincial department, was framed and stigmatized as a "traitor". He was kicked out of the police force and lived incognito in the border town of Qinghe, where he lived for three years. He always believed in his innocence and had doubts about the mysterious death of his former partner Chen Mo. One rainy night, he unexpectedly received an anonymous letter, which contained Chen Mo's chipped and blood-stained police badge and a note that read "You owe me your life, it's time to pay it back." His silent hope was rekindled. Afterwards, Li Fugui, a wealthy businessman in Qinghe Town, was murdered mysteriously. The people who came to handle the case were actually Lin Xiao, his classmate from the police academy who framed him, and his cronies. Cheng Tian sneaked into the murder scene and relied on his special "logical backtracking" ability to discover that Lin Xiao was the real culprit behind the scenes and that there was a huge conspiracy hidden behind him. In the desperate situation of being chased by Lin Xiao, Cheng Tian was rescued by reporter Su Wan who claimed to be Chen Mo's sister. The two reached a cooperation and were determined to jointly investigate the truth. They conducted an in-depth investigation into Lin Xiao's collusion with the gangster Dongxing Society, and revealed a money laundering conspiracy called "Qingyuan Project" and the mysterious "Lighthouse Organization". In the process, they experienced the test of life and death, sneaked into the casino to obtain clues, and broke into the villa at night to search for evidence, but they were repeatedly in danger. Just when the two thought they were isolated and helpless, Cheng Tian unexpectedly received a call from Chen Mo and learned that he was not dead that year and had been secretly investigating. In the end, Cheng Tian and Su Wan joined forces with Chen Mo who was abroad, holding key evidence and preparing for the ultimate showdown with Lin Xiao and the Lighthouse Organization to clear the names of the wronged and seek justice for the deceased.
