It's 1938, and things are looking bleak for humanity. The discovery that the alien Neuroi have a vulnerable "core" gave hope to soldiers and citizens alike, but there is no clear plan to push back the Neuroi's relentless advance. In the meantime, a new threat emerges when the giant "Mountain" Neuroi begins to cross the Fuso Sea, threatening the heart of the Empire itself. Forced into a stalemate an a grinding war of attrition, the Witches develop a desperate plan that hinges on two things: the cooperation of the Fuso Imperial Navy, and Mio Sakamoto's Magic Eye. Read on for the stunning conclusion of the "Fuso Sea Incident", a major turning point in the war against the Neuroi--and the lives of Mio and the rest of the Strike Witches!