Command and Conquer: Generals – Zero Hour is the expansion pack for the computer game Command & Conquer: Generals. Zero Hour added several new abilities to each side, and a new mode of play called Generals' Challenge. In Generals' Challenge the player takes on the identity of one of nine generals (three representing each faction) and does battle against most of the other generals, eventually confronting a powerful "boss" general, General Leang.
Zero Hour also contains 3 new campaigns of five missions each, one for each side, with their chronological order being USA first, GLA second, and China last. Unlike the previous campaigns, which were noted by Command and Conquer fans for not having full motion video cinematic sequences during mission briefing, the Zero Hour campaigns return to that Command and Conquer tradition, each showing a live-action video of a news reporter of the respective side giving details about the situation behind the current mission. The plot behind the Zero Hour campaigns picks up where it left off at the end of the previous campaigns.

At the beginning of the USA campaign, the Global Liberation Army (GLA) launches a biological weapon using a refitted Soyuz launch station from the captured Baikonur Cosmodrome in Kazakhstan at a USA military base located in Northern Europe. The United States Army retaliates quickly, destroying the launch platform, before the GLA can fire another missile. As the campaign continues, the United States learns that a GLA general codenamed "Dr. Thrax" has been developing a more lethal variety of anthrax known as "Anthrax Gamma". When the USA locates his base of operations, they discover that he is planning on launching several missiles loaded with this toxin at major population centers within the USA itself. A swift strike by the USA, with the help of rogue GLA forces, succeeds in preventing this atrocity, and brings an end to "Dr. Thrax".
In the GLA campaign, the GLA, though disappointed by the death of Dr. Thrax, receives a boost in morale with the successful appointment of their new leader, General Mohmar "Deathstrike". The GLA first attempts to reunite its splintered factions under Deathstrike's command, which it succeeds in doing after eliminating the defector Prince Kassad's forces in Egypt, and then begins a fervent mission to drive the Americans from Europe. Despite their lack of technology, the GLA succeeds in inflicting tremendous harm against the USA, by capturing an American particle uplink cannon which they then use to destroy the USS Ronald Reagan (splitting her in half from starboard to port, as shown in the game's cover) and infiltrating the US West Coast to steal toxins from a chemical storage facility. This reaches its climax when the GLA overruns the USA’s European central command base in Stuttgart-Vaihingen, partially with the use of captured Chinese weaponry. The GLA's primary objective accomplished, they now begin to invade a vulnerable Europe and create a new repressive state.
In the Chinese campaign, the Chinese People's Liberation Army (PLA) sends its army into Europe to relieve the USA and gain revenge against the GLA for their humiliating use of Chinese technology in the capture of the German military base. In order to prevent the GLA from making use of advanced USA weapons, China launches a nuclear missile at the military base, destroying it, and then sends its forces into Germany, where the GLA invaders are concentrated. After a series of devastating losses, the nearly defeated GLA takes control of an evacuated USA military base and uses its weaponry against the Chinese army. China succeeds in destroying both the GLA and the captured USA base, and eliminating the GLA for good, rooting out their influence in Europe. Establishing the Eurasian Unity League with the newly liberated Europe, the world looks forward to a new era of Chinese leadership.
Command & Conquer: Generals is a real-time strategy (RTS) video game and the seventh installment in the Command & Conquer series. It was released for Microsoft Windows and Mac OS operating systems in 2003 and 2004. While the Windows version of Generals was developed by EA Pacific and published by EA Games, the Mac OS version was developed by Aspyr Media and published by MacSoft Mac OS. In the game, the player can choose from three different factions: the United States, China and the Global Liberation Army (GLA).
Generals utilizes SAGE (Strategy Action Game Engine), an extended version of the Command & Conquer: Renegade's 3D engine. An expansion pack, entitled Command & Conquer: Generals – Zero Hour, was additionally released for PC in 2003, and for Mac OS in 2005. Both Generals and Zero Hour were met with highly positive reviews. A sequel, Command & Conquer: Generals 2, was in development, until it was repurposed to a free-to-play game known as simply Command & Conquer. The new game will be based around the Generals franchise and is expected to launch in 2013.
Generals takes place in the near future, with players given a choice of three factions to play. In Generals, the United States and China are the world's two superpowers, and are the targets of the Global Liberation Army (GLA), an omnipresent borderless terrorist organization, fighting as a fanatical irregular force. The United States and China are depicted as allies in the series who occasionally co-operate against the GLA, whose goals is the elimination of the military forces of China and the United States.
The game begins with a devastating GLA nuclear attack on Beijing and a subsequent GLA attack on the Three Gorges Dam. The player assumes the role of a Chinese general who rallies the remaining Chinese forces and counterattacks. The general eventually destroys the GLA cell masterminding all Pacific Rim operations.
The player then assumes the role of another GLA general who regroups GLA forces in Central Asia and gathers funds and biological weapons. In doing so, he has to face both American and Chinese armies and a GLA splinter cell. His campaign eventually culminates in the overtaking of the Baikonur Cosmodrome and the firing of a Soyuz rocket bearing a biological MIRV at an unnamed city.
At this point the American campaign begins in which the USA engages the GLA across the Middle East and the Central Asia. A joint American-Chinese operation eventually destroys another GLA command base in Astana, Kazakhstan.