Second Modern War
All over the world.
Decisive Regular Army victory
  • The Rebel Army allied with the Mars People against the Regular Army. When betrayed by the Mars People, the Rebel Army briefly allied with the Regular Army to defeat the invaders.
  • General Donald Morden is rescued from the Mars People and escapes with the Rebel Army to regroup.
  • The Mars People retreat back to outer space. They would return again in the Third Modern War.
  • The Arabian Infantry's leader Abul Abbas surrenders to the Regular Army after an attack was led against his infantry in Saudi Arabia.
  • The Japanese Army surrenders to the Regular Army, leaving its 6th division unaware of the end of the war.
Beligerants in
Regular Army
Rebel Army
Mars People
Arabian Infantry
Japanese Army

The Second Modern War is an event taking place in the year 2029, after the First Modern War, and is the setting of Metal Slug 2 (and its remake, Metal Slug X).

The influence of Morden's Rebel Army had already been eradicated, but those sympathetic to his condemnation of the rot among the General Forces' leaders and governments worldwide were surprisingly numerous and led to an endless series of fitful, small-scale uprisings.

Recently these seemingly-insignificant conflicts have become more organized and calculated. A comprehensive analysis of data from around the world suggested these clearly indicated the existence of some plan for a large-scale operation. And there was only one man capable of planning, executing, and leading such a massive operation: General Morden, who had been captured and imprisoned at the end of the First Modern War but inexplicably escaped before he could be tried for his war crimes. Many rumors surrounded his escape, including that of alien involvement, but the truth was that Morden was still alive and still attempting to overthrow the government forces.

Sometimes after his escape, General Morden made an alliance with the Arabian revolutionaries' commander Abul Abbas along with the Japanese Army, in order to invade the world with more ease. The Arabians were tasked to maintain position in Saudi Arabia (also helped by a few groups of Rebel soldiers), while the Japanese Army were given the thumbs-up to send Japanese troops in South America.

The Regular Army sends out the Peregrine Falcon Squad. Marco Rossi and Tarma Roving, the soldiers responsible for quelling Morden's original campaign, are entrusted with a secret mission to thwart the insurgent forces and nip this second coup in the bud before it can begin. It was predicted to be nasty business to wage this series of preemptive attacks on insurgent operations with a small squad of elite troops and crush all opposition, and so the highest secrecy was required. Even their bosses were not informed of the full mission so as not to let any information leak out to Morden's forces. More important, this was to stay secret to prevent people who still now trembled with fear at the mere mention of Morden's name from falling into wholesale panic. To ensure secrecy,the mission was carried out jointly with the Intelligence Agency's Special Ops Squad S.P.A.R.R.O.W.S who had selected Fio Germi and Eri Kasamoto.

Through multiple conflicts, the group learns that Morden has formed an alliance with the alien race known as the Mars People, who also desire to conquer Earth. Upon finally locating Morden in his main base, the Mars People turn on him and take the General prisoner. Now faced with a common enemy, all the members of the Regular and Rebel Armies pool their forces together to fight off the Mars People and destroy their mothership. As the dust settles, Morden and the Rebel Army escape before they can be apprehended.

The Japanese Army and the Arabian Infantry both surrendered after learning about the Rebel Army's defeat.