Superstates compete for the world's resources, and two individuals are sent to investigate when five bases of one nation are attacked unprovoked by persons unknown.

Towns and cities act as intermission points where the player can organize and set up their units for the upcoming mission.

A unit's AP amount and recharge value depends on how many AP-specific abilities its pilot has learned.

Jetpacks have built-in verniers that allow a wanzer to scale buildings and directly bypass obstacles such as water.

[3] Since the revelations of the true causes behind the 2nd Huffman Conflict in 2092,[b] the world grew wary of the Republic of Zaftra.

Zaftra began losing foreign investments and many businesses withdrew from the union, resulting in major economic losses.

Superpowers such as the United States of the New Continent (USN)[c] refused offers from the union to import their natural resources, the major economic driver of their economy.

With a failing economy and growing distrust from the world community, the Republic of Zaftra disbanded the Peace Mediation Organization (PMO) in 2094.

Meanwhile, the discovery of natural resources in Poland led the European Community (EC) to stop importing raw materials from Zaftra.

In 2096, the Republic of Zaftra returned to the spotlight after a mysterious blitzkrieg of EC military bases leaves Europe in an imminent resource crisis.

The plot of Front Mission 4 revolves around two individuals - Durandal recruit Elsa Eliane and USN sergeant Darril Traubel.

The EC leadership discuss the attacks and appoint the union's Durandal military research unit to lead the probe.

In a news conference, Glaeser's revelations that the attackers were USN puzzle the Durandal, who believe they were of Zaftran origin.

Darril Traubel and his two of friends are on patrol duty when they witness a Venezuelan State Army (VSA) transport crash in the jungle.

Darril decides to help the villagers and in the process, meets the Alianza de Libertad Venezolana (Venezuelan Liberation Alliance) rebel group.

As the game's plot thickens, the protagonists discover that Glaeser lied about the investigation and pieces its connections between the base attacks in Germany and the deserters' pursuers in Venezuela.

[11] In December 2003, Square Enix showed off video of the game alongside Front Mission Online at Jump Fest.

[20][21] North American reaction to the game was consistent across the board, receiving mixed to generally good reviews.

On the disapproving side, many felt the plot advanced at a sluggish pace, the AI was subpar, and the menu system was cumbersome at times.

The critic consensus seemed to be that fans of mecha or strategy RPG games would be pleased with Front Mission 4 and that the general audience should rent it first.