Lu Li, a food delivery guy with a dual personality, is usually timid and submissive, but whenever danger strikes, he transforms into a cold-faced master detective. One rainy night, he stumbles upon a murder at a villa and exposes the truth behind a wealthy man's supposed suicide: his son delivered the fatal blow. This catches the attention of policewoman Lin Xia. An old photograph at the police station reveals that Lu Li looks exactly like an investigator who died in the line of duty three years ago. When Xiao Yue, an internet celebrity, mysteriously dies during a livestream, everyone turns to ghosts and superstition for answers. Lu Li digs deeper into the clues and awakens once again, exposing Old Song, a technician who killed out of jealousy. A peculiar mark on the physical evidence triggers a severe headache, while two mysterious men, Qi Ye and Qin Feng, secretly keep watch over him. The fog surrounding a sealed case from the past slowly begins to lift.