In the urban fog, a private reasoning team "Grayscale Investigation Team", united by their own secrets and ideals of justice, assists the police, victims and all walks of life to solve a series of cases of disappearance, homicide, blackmail, and social corruption. Whenever the case comes closer to the truth, new mysteries and dangers follow. The team not only struggles with the boundaries between law and emotion, good and evil, but is also deeply involved in a crisis of self-salvation and trust. A major case affecting the foundation of the city gradually emerges, and the secrets of the members are gradually exposed - in the end, everyone will stand at the crossroads of fate and justice at the end of the fog and make their own choices.
