Shingo Saku is the Police Commissioner at the Metropolitan Police Department headquarters. Within the force, he is known as the youngest top management and his nickname is "The Tactician". One day, the corpse of a man called Yasuyuki Okamoto was discovered in an area under the jurisdiction of the West Marunouchi Police Department. The policemen in charge had ruled the death as suicide and were about to close the case when the MPD Director, Toshiya Yanaka, stepped in and set up a team to investigate the death. Shingo was called in to head the investigations. The First Division's Section Chief, Makoto Shimano, and the 13 staff under him were assigned to the case. Understandably, they were all upset that they had to report to a non-career (someone who goes on administrative career path instead of detective work), thus Shingo's only ally is his chauffeur-turned-detective, Daichi Yashiki. To top it all off, the West Marunouchi Police Department's men were also up in arms to have had their judgment questioned. Shingo has his hands in trying to bring everyone together and work as a team.