Six months after the conclusion of the L5 Campaign and the DC War, the crews of the PT carriers, Hagane and Hiryuu Custom have gone their separate ways. They are not far apart for long, however, as the remnants of the DC soon begin to push against the Federation Forces with newly acquired resources. A mysterious organization, the Shadow Mirror, has begun to arm them with weapons and robots that should not exist. Compounding matters, inter-dimensional entities known as Einsts begin to appear around the World and seem to share a psychic connection with ATX pilots, Kyosuke Nanbu and Excellen Browning.