In the modern city of 'Azure City', a private investigation team - the 'Mystery Tracking Bureau' was born due to a crisis of social trust. Many bizarre cases challenge the police and public perception: a missing painter, a school death mystery, a black market murder, a revenge mystery, a transnational cyber murder... Team members are responsible for reasoning, psychological analysis, evidence collection, technology, intelligence and other tasks, gradually revealing the intricate human nature and social issues behind the cases. As the case progresses, the main line gradually points to an unjust case that has been buried for many years - their past is secretly intertwined with each case. The team grows between the boundaries of truth and morality, and faces their own unavoidable knots.
