Wu Jichuan and Ye Jiu were childhood friends who grew up together. They talked about everything but were separated for some reason. When they met again, they looked at each other with strange eyes on the last train. Ye Ji's appearance became the only light to dispel the chill around him. The two regained their friendship side by side, and together they investigated bizarre cases and followed clues to uncover the secrets of the past and old grudges between humans and ghosts that had been sealed for many years. They wander in the gap between the worlds of humans and ghosts, facing the intrusion of evil and unknown crises. On the way to solve the puzzle, their youthful friendship is tempered into deep love. Only by holding each other's hands can they find a way out and protect each other in the gloomy fog.
