Based on the Gameboy Advance game Super Robot Wars Original Generation 2
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. Even worse, aliens calling themselves, The Inspectors, have arrived from outer space with plans to retake the White Star and finish the job the Aerogators could not. As this new, four sided war begins, Lamia Loveless, a Shadow Mirror operative sent to spy on the Federation Forces must choose between her orders and her new found friends among the Hagane and Hiryuu crews.