Kazuo Izawa has a good life running a simple photography store in London... until he's suddenly arrested under suspicion of espionage. As Isawa undergoes a harsh interrogation, Lieutenant colonel Howard Marks, master spy for the British Secret Intelligence Service, appears before him.

Aaron Price, Far East correspondent for the British Times, investigates the true identity of Lieutenant colonel Yuuki, the man rumored to have founded D-Agency. Flipping through the Military Preparatory School's list of past enrollees, his eye is drawn to a boy who passed the entrance exam at the top of his class, but was expelled for violence. His name? Akira Arisaki.

Karl Schneider, writer for the Berlin Allgemeine, is suspected of being a German/Soviet double agent. While D-Agency searches for proof of his espionage activities, Schneider suddenly dies under mysterious circumstances. Lieutenant Colonel Yuuki sends his men on individual missions in order to uncover the truth.