In 1944, Japan was destroyed by an unprecedented disaster, which immediately put an end to the war.

Devastated in the aftermath of defeat, the Japanese government complies with the Allies’ reconstruction plan and the country begins to recover from the loss after a few years, but America and China intricately divide the nation on a municipal level. Eventually, China’s military districts become Chinatowns, and places controlled by the United States are Americanized. The many Chinese and American immigrants make Japanese people the minority in Tokyo.

In Tokyo's District 23, a girl named Rose Haibara, who leads the Club Primavera, an establishment for ladies of the night, one day meets with Leo Shishigami, a laid back repatriated soldier with nowhere to go. There begins the story of Rose's determination to help her countrymen in need with Leo's support.  (From: MU)

Based on visual novel of the same name by 07th Generation. This manga covers the 1947 arc, which spans "Season 1" and "Season 2" of the VN.
Licensed in English by Yen Press as Rose Guns Days Season 1.