The rain and fog in the old alley have not cleared for twenty years. Psychology expert Chen Yanan reunites with his old acquaintance, detective Lin Xunye, because of the muffled sound of a bunch of walnuts. Clues to past unsolved cases emerge in the present. The two use psychological profiling and criminal investigation logic to uncover the truth hidden by time in the depths of rain and fog.
Intent: A pursuit across time is the salvation of each other, and it is also the glimmer of light that jointly dispels the haze.