Yun Hongshen and Gong Chuchang embark on a mission together. In the car, Yun Hongshen offers Gong Chuchang some chocolate, but he declines. Yun Hongshen eats a few pieces as a snack and throws the wrapper out the window. Gong Chuchang signals to the passenger in the front, who understands immediately. Feigning a stomachache, he asks to use the restroom. Though annoyed, Gong Chuchang instructs the driver to stop. The passenger gets out and retrieves the chocolate wrapper.
However, Yun Hongshen also tossed out a rolled-up piece of paper. Xiao Dao quickly retrieves it and delivers it to Wu Secretary and Yun Hongqi, who are waiting nearby. Yun Hongshen instructs them to go to Milan’s house to alert Zong Fang. Xiao Dao, initially thinking Milan is still alive, learns that it’s Zong Fang who is at her house. They go to Milan’s house, successfully alerting Zong Fang and then leaving after observing his departure.
By the time Yun Hongshen and Gong Chuchang arrive, Zong Fang has already escaped. Yun Hongshen notices thumbtack marks on the wall and deduces that Zong Fang had hung a map there, marking specific locations. He asks his subordinates to find a map of the same size and uses thumbtacks to recreate Zong Fang’s markings.
Gong Chuchang observes that Zong Fang’s teacup is still warm with freshly brewed tea and wonders why he left so abruptly. He orders his men to investigate.
Back at the military command, Yun Hongshen shows Ke Jingping the map, suggesting that Zong Fang may be planning explosions at the marked locations. They question how Zong Fang could single-handedly bomb so many places. Yun Hongshen admits he doesn’t have an answer yet.
Reviewing Ling Han’s activity records before his death, Yun Hongshen finds a valuable clue. He calls the library to inquire about the materials Ling Han had been reading for an hour. The librarian informs him that Ling Han was researching the differences between Eastern people. Yun Hongshen realizes that Ling Han must have discovered Ke Jingping’s true identity and was trying to find distinguishing features that set Ke Jingping apart from the Chinese. A sudden realization hits Yun Hongshen, and he rushes to the meeting room.
Pointing to the marked locations on the map, Yun Hongshen explains Zong Fang’s plan to Ke Jingping. Zong Fang intends to plant the thirty kilograms of explosives he obtained in the sewers at these locations. An explosion at any one of these points would ignite the sewer gas, creating a chain reaction and devastating Changsha.
Ke Jingping orders an immediate operation to clear the sewers of explosives. Yun Hongshen suggests that Zong Fang might target the military hospital as the trigger point. They all arrive at the hospital, and Yun Hongshen points to a spot on the map, asking Captain Tang if there are any easily overlooked areas nearby. He then speaks cryptically to Captain Tang, who wonders if Yun Hongshen has discovered his true identity, hoping Wu Secretary hasn’t informed him yet. Captain Tang identifies a nearby power station that fits Yun Hongshen’s description. They head to the power station and indeed find Zong Fang there. Zong Fang takes Gong Chuchang hostage and demands his release, but he is ultimately killed.
Yun Hongshen expresses concern about facing Ke Jingping without the encryption key. Gong Chuchang takes responsibility for the failed operation and assures Yun Hongshen that he will report to Ke Jingping. Upon learning of Zong Fang’s death, Ke Jingping doesn’t blame them, expressing relief that they returned safely. Yun Hongshen, feeling uneasy, declines Ke Jingping’s invitation to visit Wen Yeming at the hospital, claiming he has unfinished work. He knows that to prove Ke Jingping is Kun Wu, he must access Ke Jingping’s secret room.
After Ke Jingping leaves, Yun Hongshen enters the secret room. There, he finds evidence confirming that Ke Jingping has been manipulating everyone like chess pieces. Unbeknownst to Yun Hongshen, a pair of eyes is watching him from the shadows.
