Episode 4 recap: Qi Heng discovered some suspicious points in the case.

Later, Marathon asked Qi Heng about his love for his wife and how they got married. Qi Heng recounted the process of their first meeting and falling in love. Marathon mentioned that he had been pursuing Guo Nian and that passive feelings like that couldn't last. Qi Heng admitted that Guo Nian valued her career a lot, and they had always been apart most of the time. Initially, they would have cold wars, but later it turned into long periods without seeing each other, and she even accidentally fell and broke a bone.

Marathon mostly blamed Guo Lun for the responsibility, but later he apologized to Guo Lun on his own initiative. Guo Lun mentioned that his sister had been kidnapped, but he still believed she was alive. Marathon naturally believed him and even said he was willing to help Guo Lun find his sister. This warmed Guo Lun's heart.

In fact, it was Luo Huaigong who had Zheng Duo handle Guo Nian's situation. Previously, Guo Nian, as a journalist, had investigated some improper internal activities of Luo Huaigong's company, so Luo Huaigong sought Zheng Duo's help to deal with her. Luo Huaigong only recently found out that Guo Nian was Qi Heng's wife, so he had to bring Qi Heng down; otherwise, it would be a thorn in his side, especially since Zheng Duo was still in Qi Heng's hands.

When Qi Heng was driving Marathon back, he asked about the relationship between Guo Lun and them. Qi Heng said that Guo Lun and Guo Nian had a very good relationship, and he treated Guo Lun well too. However, he felt that Guo Lun didn't regard him highly. Marathon, on the other hand, believed that Guo Lun definitely had feelings for Qi Heng and told him that he could always come to him if he needed any advice.

In the morning, Qi Heng noticed that Guo Lun had neatly folded the blankets and cleaned the dishes. In fact, Guo Lun had also been bullied in prison because his brother-in-law was Qi Heng. Guo Lun said that the only thing that remained unchanged for him was to find his sister. Lin Yu had already given the police a detailed account of the entire process of Wang Guiping's murder, which was advantageous for the overall situation.

Luo Huaigong invited Ling Auntie from the Cultural Relics Bureau to his house to see antiques. Later, he also invited Ling Auntie's daughter to join them for dinner. Ling Auntie's husband, Wu Shenyuan, was comrades with Luo Huaigong's father. It was Luo Huaigong's father who saved Wu Shenyuan, which is why Wu Shenyuan was unharmed. However, Luo Huaigong's father passed away due to illness.

Luo Huaigong originally wanted to give Ling Auntie a pair of antiques as a gift but was refused. Marathon arranged to meet Guo Lun and even gave him a gift. Marathon mentioned that he had a rough idea about the situation and also wanted to know the process of his sister's disappearance since she promised Guo Lun to help find her. After hearing Guo Lun's account, he got a general understanding of the situation. In fact, Qi Heng was also looking for Guo Lun's sister. Marathon told Guo Lun that he should stand up as soon as possible and promised to introduce a programming master to Qi Heng. However, the condition was for Guo Lun to reconcile with his brother-in-law, Qi Heng. Guo Lun reluctantly agreed.

Niu Geng received a call informing him that the prosecutor's office was going to file a lawsuit for intentional injury. Qi Heng told everyone not to worry for the time being and that they needed to plan for the long term. When Guo Lun returned home, he asked Qi Heng for money, saying that he wanted to start a company. Tomorrow was Guo Nian's birthday, and Guo Lun originally wanted Qi Heng to accompany him to the amusement park where his sister disappeared. However, Qi Heng refused because of work, which made Guo Lun even more upset.

When Qi Heng went to the police station for investigation, he wondered why Zheng Duo insisted on using a camera to take photos and why he gave the spring knife to Hu Bai. In the end, he even implicated Hu Bai in Wang Guiping's murder. Based on Qi Heng's speculation, they suspected that Zheng Duo was likely an assassin, and his target was to kill Hu Bai. They just didn't expect so many things to happen on the boat.