In the Darkest Shadows... The Prelude to War Begins! The year is 1931. The City is Shanghai. Ten years before America will enter World War II, the hydra’s teeth planted by the first great global conflict are beginning to germinate, hatching into spiders weaving the complex web of plots and conspiracies destined to inevitably draw entire nations, against their will, to the brink of destruction once more. And caught in the heart of these webs, desperately seeking to separate lies from truth, is "Sakurai Kikan," an ultra-secret intelligence agency staffed by extraordinarily talented individuals with abilities far beyond those of normal humans. Their duty: stop the darkest plots and eliminate the greatest threats. But in a city built on intrigue, can even a team of clairvoyants, telepaths and espers stand against the ultimate forces of destiny? As the Japanese Imperial Army rolls across China, documented facts and fantasy intermingle in the breathtaking exploration of alternative history that is NIGHT RAID 1931!
The Sakurai organization is tasked with a covert mission to rescue a Japanese business president from the hands of a small Chinese military faction.
The members of Sakurai organization - each acting individually - board a ship en route from the Port of Kobe to Shanghai. Their first mission is to investigate women who left for Shanghai by way of Kobe and Nagasaki, and were never seen again.
Sakurai requests the group to investigate a Jewish Russian violinist named Sergei Krainev, who the Kwantung Army suspects is a foreign spy. The members of the Sakurai organization will need to use all of their skills to crack this case.
Yukina receives a letter from her missing brother, but overshadowing all that is a bomb threat involving four major department stores in Shanghai. While trying to stop the bomb plot the members encounter an adversary who may have powers similar to their own.
A cat takes the bag containing film of Feng Lan's menu as well as the film containing photos of a Japanese lieutenant. Aoi and Kazura are forced to investigate the Green Gang to recover the film. They are lead all over the city in search of the missing bag and their film.
Kazura recognizes his old friend Nishio in a photograph that Aoi has taken in a German delegate's house, resulting in Kazura investigating Nishio's whereabouts against the wishes of Mr. Sakurai.
Isao kidnaps Aoi and lets him listen to the Asian delegates' meeting, where he voices his ideals on Pan-Asianism, and encourages Aoi to join in his group. Kazura, Natsume and Yukina are confronted by one of Isao's men, who refuses to let them interrupt the meeting in a battle that tests all of their powers.
Two reporters run into Kanji Ishihara, the Lieutenant Colonel of the Kwantung Army. He helped devise a bombing so that Japan could attack Manchuria. Ishihara and several other high ranking officials come face to face with the prophetess.
The Sakurai Ogranization investigates a religious organization that is a front for an Opium Den where spies are known to frequent. Yukina faces some strange revelations in reading the minds of the people there.
After the Mukden Incident, Japan uses the opportunity to seize the entire Manchuria region. The League of Nations sends in Sir Lytton and his committee to investigate the situation, but Sir Lytton will soon see sights he could only imagine in his nightmares.
Aoi follows the convoy where his fiancée Shizune is, but he loses track of her. Going undercover, he infiltrates the building she is residing in, but is confronted by Kazura. Despite Kazura's attempt to stop him, Aoi escapes with Shizune.
During the group's next mission to find evidence that the Chinese are smuggling in weapons from Germany, Kazura is ambushed by a group of Westeners. When Isao comes to his aid, he reveals to Kazura a secret base where nuclear weapons are being developed. His words force Kazura to make some decisions that he may regret.
The war between America and Japan is inevitable, and that they must prepare for it. Aoi and Natsume infiltrate Isao's base, where his subordinates are setting a bomb. In the moments before the blast Kazura faces his past.
Isao and his men continue to act discreetly as round-the-clock construction work occurs in Xinjing in preparation for Puyi’s expedited inauguration ceremony as the new emperor of Manchukuo.
Aoi and Kazura combine their efforts to hijack the plane containing the atomic bomb and drop the weapon in the ocean. Loyalties are tested and the stakes are high.
Back in Japan, Yukina visits Natsume's family to give back his belongings. Meanwhile, Kazura receives a mission from the Kempeitai to investigate a group of young military officers who were planning to start a coup d'état.