It is the age of the steam engines, an age of progress and prosperity, and everything seems to be just fine. But secretly, the evil forces are preparing their attack...

The hopes of the Capital Defense Force lie within the new weapons developed by Kanzaki Heavy Industries: the armed airship Shogei Maru, the bullet train Goraigo, and the spirit armor Oobu. A strong spirit is required to control the Oobu; that's where a group of six young girls come in: Sakura Shinguji, trained in the Northern Long Blade Style all her life; Sumire Kanzaki, trained in the Kanzaki Raising Wind Naginata Technique since childhood days; Maria Tachibana, an excellent gunner; Iris Chateaubriand, a psychic girl with skills in telekinesis and teleportation; Ri Kouran, a genius in electrical and steam engineering and chemicals; and Kanna Kirishima, a martial artist of amazing strength in the 28th generation of the Kirishima Martial Arts School. They're the Capital Defemse Force's Floral Assault Group.