Pet detective He Xun helps Tang Xiaotang find her lost cat Doubao, who has been missing for three days. He does not rely on complex equipment, but patiently questions security guards and neighbors, tracking clues step-by-step from the community. Through successive searches and safe rescues, Su Yinuo, Aunt Chen, Security Guard Liu, and Lin Meimei also join in to assist, and the lost pets gradually return to their owners' sides. He Xun discovers that besides searching, preventing loss is equally important, so everyone establishes a community pet archive, registering pet characteristics and contact information. Eventually, the community forms a mutual aid network, and He Xun continues to guard the daily companionship between people and pets.