A research installation developing the next-generation of Metal Slugs is attacked by unknown forces and a disk containing Metal Slug secrets is stolen. 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. The military subsequently launches a second raid by the elite PF squad and Sparrows on the 'The Corridor of Fire' to recover the secrets and destroy the syndicate!!!
This new episode introduces a new 'slide' move to the legendary series (actioned holding down the B button). Players can also make a sliding shot by pushing the A button while sliding. (arcade-history)