The year is 193X in Shanghai, the city where lives are valued least. The rivalry between the two factions controlling the underworld, the Green Gang and Red Flower Gang, reaches its peak and is nearing its end with a Green Gang victory. The individuals responsible for the revival of the Green Gang, Kasumi Kenshirou and Yu-Ling, are enjoying a brief rest from the conflict. Meanwhile, in Harbin, Liu Fei-yan and Erika Arendt are carefully transporting something. With their course set for Shanghai, they are headed to meet French intelligence officer Charles de Guise.
Summary taken from: MyAnimeList