19 years ago, the angelic sister of the Xuan family was murdered bizarrely. The murder case was stagnated for many years, and the murderer remains at large. As a result, the Xuan family spread out from north to the south, living on their own. 19 years later, a bizarre case occurred in a small town ropes in the Xuan family again, causing the divided family to reunite in their hometown. As the truth of the old case gradually surfaced, years of conflict between the tormented brothers and sisters finally broke out. Where will the family of four go? Can they untie the knot they have and get out of this thick mysterious fog?