Lost World

In an alternate reality, Hiroshima city is the only city left of Japan after an all-out nuclear attack during the World War II. Japan has been military rivals in the Pacific for more than a century with the major power houses such the Soviet Union and the United States. Now that Hiroshima City is the only thing left of Japan, its rivals are coming to finish it off. 

However, there are spies in Hiroshima City who are feeding classified intel off to the Soviet Unions and U.S. Therefore, it is important that they are found and eliminated. From then, a group of specialists will be formed and defend Hiroshima from what is coming next.