Ordered to recover the disk, Marco and Tarma follow in hot pursuit. Meanwhile, Eri and Fio, investigating the Ptolemaic Army, a paramilitary syndicate active in archeological excavation, catch up with them at an ancient ruin, "The Corridor of Fire." The two try to storm and seize the site but are repulsed by the natives and giant Metal Slugs. This incident proves it was the Ptolemaic Army that stole the Metal Slug secrets.