The Global Defense Initiative began as a secret military alliance of advanced nations under the United Nations umbrella. GDI's mission: To contain Tiberium, reverse its spread, and fight the sinister Brotherhood of Nod.

Over time, power and sovereignty have been gradually ceded to GDI and the national identities of the participating countries have faded. In 2047 that process has reached its final stages: While there are still technically individual Member Nations, the reality is that GDI has become a unified political and military super-state.

GDI controls the only areas of the Earth that have not been significantly compromised by Tiberium infestation. The crystalline alien substance is slowly consuming the rest of the planet, causing an environmental cataclysm that has made 30% of the Earth uninhabitable and another 50% of the Earth's surface exceedingly unfriendly to civilization. GDI's home territories are known as "Blue Zones" since they are mostly clear of Tiberium and have been relatively untouched by war (in contrast to the ecologically ravaged and war-torn "Yellow Zones" and the Tiberium infested hellscapes designated as "Red Zones").

The clash between GDI and Nod has escalated into full world wars twice before - the First Tiberium War (TWI) erupted when both powers were in their formative states and that terrible war was followed by another worldwide firestorm several years later.

全球防御組織開始于一個(gè)發(fā)達(dá)國(guó)家在聯(lián)合國(guó)保護(hù)傘下的秘密軍事組織。GDI的任務(wù)：遏制泰伯利亞并逆轉(zhuǎn)其傳播，和對(duì)抗邪惡的Nod兄弟會(huì)。

隨著時(shí)間的推移，權(quán)力和主權(quán)逐漸轉(zhuǎn)讓于GDI，參與國(guó)的國(guó)家身份開始消失。在2047年，進(jìn)程已到達(dá)最后階段：雖然仍有法律意義上的獨(dú)立成員國(guó)，事實(shí)是GDI已經(jīng)成為了一個(gè)政治軍事統(tǒng)一的超級(jí)大國(guó)。

GDI控制著僅剩的地球上未被泰礦嚴(yán)重污染的地區(qū)。這種水晶般的外來物質(zhì)正在緩慢轉(zhuǎn)變剩下的地區(qū)，造成一場(chǎng)環(huán)境災(zāi)難，使地球上30%的地區(qū)不宜居住，剩下50%的地區(qū)對(duì)文明非常不友好。GDI的領(lǐng)土被稱作“藍(lán)區(qū)”，既沒有被泰礦大量污染也相對(duì)沒受到戰(zhàn)爭(zhēng)影響（與生態(tài)破壞戰(zhàn)爭(zhēng)摧殘的“黃區(qū)”和泰礦污染地獄的“紅區(qū)”相對(duì)比）。

GDI與Nod的沖突曾兩次升級(jí)為世界大戰(zhàn)——第一次泰礦戰(zhàn)爭(zhēng)（TWI）爆發(fā)之時(shí)兩勢(shì)力還在形成期，這次可怕的戰(zhàn)爭(zhēng)幾年之后又形成了全球的火焰風(fēng)暴。