Zheng Yan died mysteriously. Lu Xun suspected dancer Feng Ruyue and her brother Kongkong, with the latter missing. Following the clue, Lu came to Heize with Dashan and Ruyue. They saved Tang but Tang kidnapped them. They learned Kongkong was also captured by Tang to blow the capital up. To prevent it, they fled. Lu exposed the plot of the Fengs to kill Zheng. Ruyue confessed her birth father was framed and killed by Zheng. Lu was confused at the identical stories and said his father left him a secret letter. The two went to fetch the letter and met Guishou, Ruyue’s father who works for Tang. Led by him, they came to the underground treasury and found Tang and Kongkong. At this time, Yecha, who turned out to be Lu’s foster father Yunzheng, appeared. In the past, Yunzheng deceived Tang to get the treasure. Tang blew the treasury up, Lu and co. subdued Yunzheng with Guishou after escaping.