After Xu Shanshan's strange messages in the group chat and the strange voice on the phone, Lu Guang, Cheng Xiaoshi and Qiao Ling are terribly worried about their friend. Lu Guang decides to go to Inspector Xiao, while the other two should stay in the photo shop for safety. But fearing that Xu Shanshan could be in the hands of a murderer, Cheng Xiaoshi sneaks away to investigate on his own...