Kuroda Kosaku, a diplomat with the Japanese Ministry of Foreign affairs receives secret orders from his superior, Ando Yosuke, to protect Japanese nationals, and moves from place to place around the world. Kuroda solves a case involving the kidnapping of a Japanese in South America, and heads to San Francisco next. His objective is to protect Mikami Shoko, the Vice Minister of Foreign Affairs, who is visiting to attend the WTO negotiations on agriculture. Kuroda, who enters San Francisco and checks on the security at the meeting, meets John, an informant, and listens to the movements of the FBI. After that, he meets Shimomura Takeshi, a former diplomat, again. Shimomura and Kuroda have a close connection from their work at the consulate in Mexico 11 years ago. When they part, Shimomura leaves Kuroda with the cryptic words, ?I?m sorry?. At that moment, the murder of a university professor occurs within the jurisdiction Tsukuda Police Precinct in Japan. Detective Ogaki Rikako of Tsukuda Police Precinct is the first person to discover the dead body. Rikako is bothered by the time of the dead body?s discovery and tells her boss about it, but is ignored. At the negotiation meeting, the Vice Minister appears to be attacked by radicals. However, Kuroda?s tact saves the day. How did the radicals infiltrate so easily? Kuroda, who suspects they had a man on the inside, is notified that a Japanese has jumped to his death ? That man is Shimomura! Meanwhile, a suspect surfaces in the murder that occurred within Tsukuda Police Precinct?s jurisdiction from the footprints, fingerprints and articles left at the scene. The suspect is Shimomura. Rikako goes to San Francisco with his daughter, Rui, in order to identify Shimomura?s body and the evidence. Kuroda is waiting for the two of them ?