Six months following the battle in Venezia, Minna-Dietlinde Wilcke, Gertrud Barkhorn, and Erica Hartmann have been stationed at the Saint-Trond Base in Belgica, alongside fellow Karlsland witch Heidemarie W. Schnaufer. Erica's twin sister Ursula delivers a giant 50mm cannon, along with a Jet Striker Unit required to carry it, with Gertrud chosen to test them, despite Erica's concerns following the last time Gertrud rode a Jet Striker. Erica is soon brought out to test a Twin Striker with Ursula, but Erica's lack of patience causes the test to fail. Erica ends up lashing out at Ursula, calling all of her inventions useless, leading her to become downhearted...