The spy inside the factory is Li Guangming, director of the factory security department.

Zhang Yan received verification information from the provincial department and learned that Li Guangming's girlfriend was in Hong Kong. Zhang Yan asked Chen Dongsheng to keep an eye on Li Guangming. Chen Dongsheng asked Pang Hongmei to inform Li Guangming to work overtime tonight, and then sent Pang Hongmei to search Li Guangming's home.Ge Yun sent Luo Shanshan and Bai Hui to the construction site to do protective work, and they were ready.The more Li Guangming thought about it, the more something was wrong. He lied that he had something to do at home and asked others to send equipment to the construction site. He rushed home overnight.

Pang Hongmei was checking his house. Li Guangming opened the door and entered the house. He had spread flour at the door beforehand. There were no traces of anyone stepping on it. Li Guangming was still worried. He searched around the room and found nothing unusual. He took it from the drawer.After grabbing a document and going out, Pang Hongmei hid aside to see clearly.Pang Hongmei found Qianqian's letter and photos at Li Guangming's home, and handed them to Chen Dongsheng immediately. Chen Dongsheng determined that Li Guangming was a lurking enemy agent.