Episode 7 recap: The substitute did not make it.

Little Seven dug up the white bones and was scared off. The next day, the passing villagers saw the situation and reported it. Wang Shi Tu and Qin Yong brought people to inspect the scene, and according to the forensic analysis, these white bones had been buried for at least two years. Wang Shi Tu noticed that the deceased was wearing a school uniform from Zhaoyang Third Middle School, which surprised Zhang Zheng, as the remains dug up three years ago were supposedly from a dog.

Senior Xu the forensic expert was certain that the pit dug three years ago was indeed in this location. Qin Yong was saddened, as he had been so close to the truth back then. Wang Jia, the sister of Wang Shuai, was called in to identify the deceased's belongings, and she recognized them as her brother's, including a thermos she had gifted him for his birthday that he always carried with him.

Wang Shi Tu promised Wang Jia that they would find her brother's killer, and hoped she could take care of their mother. Qin Yong and Wang Shi Tu unanimously believed that Wang Shuai's murder case was related to Du Yi and Bian Jie, who were considered major suspects, so they went to interrogate them separately at the police station.

Wang Shi Tu knew the current Bian Jie was unrelated to the old case, as he was not the real Bian Jie, but they still had to follow procedures and interrogate him, with Qin Yong personally filing the request. Du Yi confessed that their relationship back then was not good, and they only pretended to get along because Bian Jie's family was wealthy.

According to Du Yi's account, one night the three of them were barbecuing when Wang Shuai and Bian Jie got into an argument, and Bian Jie accidentally killed Wang Shuai. Du Yi didn't dare to report it because his fingerprints were also on the knife, and as a vagrant, he was afraid the police would think he was the killer. So he just ran away.

Little Seven told Wang Shi Tu that he was the one who discovered the remains, and he also revealed the conversation he had overheard between Jin Man Fu and Yan Zi. He suspected that Jin Man Fu and his daughter knew Bian Jie was not the real one, but they were concealing it, so they must know where the real Bian Jie is.

Moreover, Du Yi was very likely aware of the truth about Wang Shuai's murder, because Little Seven had deliberately brought up the remains when he tried to extort Du Yi at the arcade. Du Yi's obvious panic and his hurried departure made Little Seven suspect that Du Yi had gone to the burial site on Qinglong Mountain to burn a cigarette.

When Qin Yong searched Jin Man Fu's residence, they indeed found suspicious items in Bian Jie's room. Qin Yong told Jin Man Fu that the police had confirmed Wang Shuai's murder, and Bian Jie was a major suspect. That night, Jin Man Fu pondered the past events in his study and remembered that Bian Jie had brought home a knife, which was likely related to Wang Shuai's killing. Du Yi must have covered for Bian Jie for a reason.

After killing Wang Shuai, Bian Jie had returned home to get money to flee, but was seen by Yan Zi, leading to an argument. Yan Zi didn't know the details, as it was their father who had taken Bian Jie away. Now, with the current Little Seven being mistaken for the suspect, Yan Zi felt guilty.

To prove that the current Bian Jie was indeed the real one, Jin Man Fu deliberately broke the knife that Bian Jie had brought back, with Wang Jia as a witness. However, Qin Yong thought the timing of the knife's appearance was too convenient.

Now, Wang Shi Tu's efforts to prove that Little Seven was not Bian Jie hit another snag when Jin Man Fu claimed that Bian Jie was not Bian Mei Zhen's biological son, but an adopted child. With Bian Mei Zhen's ex-husband now deceased and her in a confused state, there was no one to verify this.

Little Seven realized that Jin Man Fu was trying to frame him, but he could not clear his name since he had an ID card proving he was Bian Jie.