The story takes place in an alternate 1920s Tokyo. It follows the adventures of an all-female secret task force known as the Imperial Assault Force — Flower Division as they defend the Imperial Capital Tokyo against evil. They are led by Ichiro Ogami, a newly graduated Imperial Navy Ensign who had been assigned to the squad partly due to his unique ability to use a special type of armor that only women having high levels of spiritual powers could previously operate. The setting eventually moved on to other locations such as Paris and New York.