2 years and 4 months after the simultaneous demise of Serpent and Model W, everything has returned to normal. The newly renamed Guardian Express, formerly Giro Express, is making its deliveries as expected. Suddenly, some enemy Mechaniloids storm the ship. They seem to be Galleons, but something is strange about them. Vent/Aile bravely fights them off, but they have no idea a new battle is about to begin...