Imagine a world of airships and steam trains. An endless war rages between the Empire and the Republic. The Empire has created a new weapon—ultralight fighter aircraft that only chosen girls can pilot. Sisters Vivien and Bethany go through the selection.
Parents manage to hide Bethany, but recruiters forcibly send Vivien to the Academy. And now Vivien must figure out how to keep herself intact in a world engulfed by the merciless flames of war.