In Metal Slug 4™, a cyber-terrorist group has struck out at the world by unleashing a computer virus via the Internet with the sole purpose of hijacking the military forces of the world's nations. Join Marco, Fio, and new Metal Slug team members Trevor and Nadia as you stop the distribution of the virus before it's too late.

Continue your adventure in Metal Slug 5™, in which a research installation developing the next generation of Metal Slugs is attacked by unknown forces and a disk containing Metal Slug secrets is stolen. Lead Marco, Tarma, Eri, and Fio into The Corridor of Fire to recover the secrets and destroy the paramilitary syndicate known as the Ptolemaic Army.