Timeline of Events

1995- The Retreat to Xen

The Combine Empire invades and takes control of the Vortigaunts' homeworld (which we have never seen), and attempt to enslave them, including their leader, Nihilianth. A long and bitter struggle ensues, as the Vortigaunts flee from planet to planet, battling and evading the Combine forces. With their backs against the wall, they flee to the border world Xen, where they wait their demise. Xen is sort of like a "subway station" of the universe in that it can be used to cross dimentions. Marc Laidlaw calls it "a dimensional transit bottleneck--an area of continual contention."

(A quick note about Xen: Marc Laidlaw has stated that "nothing is native to Xen" which implies that life Xen is a mish-mash of beings from all over the universe, being willingly or unwillingly transported there. I will refer to the beings from Xen as the "Xenians", which include the headcrabs, ant-lions, vortigaunts, the rest of Nihilanth's race and so on.)

The Combine attempt to hybridize the dominant species of the planet (In Xen's case, the Vortigaunts) with their own technology to create a "Super soldier" that is adapted to Xen's environment and uses powerful Combine technology. (This is what they attempt to do on Earth, as well). Nihilanth fights bitterly against the Combine.

Back on Earth, Gordon is studying for his doctorate at MIT. At Black Mesa in New Mexico, teleportation experiments are taking place. Under the supervision of researchers Eli Vance and Dr.Kleiner, crystals are retrieved from Xen, and organisms are analyzed. Research is developing.

Back on Xen, the Vortigaunts (and the Combine) discover Black Mesa's portal from Earth. The Vortigaunts see Earth as an escape route; The Combine see it as another opportunity. They contact Wallace Breen (how they do this is not known at the time), the Administrator of Black Mesa. Promising him power and riches, the Combine persuades Breen to allow the Combine to bring Earth into its "Universal Union", convincing him that this is humanity's greatest opportunity to see the stars, and embrace the universe. Breen takes the bait, believing the Combine truly want to help humanity (and not enslave them, as they eventually do). The Combine prepares to take Earth.

2000- The Black Mesa Incident

they're waiting for you Gordon, in the test chamber.

(i) Breen Triggers the Resonance Cascade - Wallace Breen, under supervision by the Combine Overlords, triggers a resonance cascade within the Anomalous Materials sector of the Black Mesa complex, by selecting a specific test sample to be used. His selection of this hazardous material is masked by a system crash, which Breen most likely triggers to cut out formal communication between scientists. A mysterious figure, G-Man is aware of Breen's plan and tries to prevent the Resonance Cascade, but fails. This "volatile portal" allows the Combine to send their initial forces to take over Black Mesa and prepare for the main invasion. Nihilanth's race seens the dimentional fissure as their big escape plan, their way out. Of course headcrabs and other life trapped on Xen decide to hitch a ride to Earth, for the fun of it. G-Man prepares a task force to deal with the main portal and prepares US soldiers to fight the aliens. Black Mesa becomes a messy situation, as many species and technologies clash.

One man in a HEV suit becomes of great interest to G-Man during the incident, however. Gordon Freeman, a newly assigned scientist in the Anomalous materials lab, shows exceptional skill in dealing with Xen beings and U.S. troops. G-Man's interest peaks as Freeman navigates through Xen (the Xenians believe that Gordon is just as much of an enemy as the Combine) and defeats the Nihilanth. G-Man is impressed.

But before this, Gordon does what he's best at, following instructions. He unknowingly helps the Combine campaign by launching a Lambda satellite into space. This mission-critical satellite is most likely what the Combine need to conduct the Portal storms by opening up portals all over the Earth.

Black Mesa is destroyed by nuclear detonation (noted in OF), but the Combine have what they need in place - an unstable portal to Earth and a satellite to conduct a portal storm with.

(ii) Gordon is Hired - At the end of Half-Life G-Man, impressed by your work, gives Gordon a choice between his death or working for the G-Man. Half-Life 2 assumes he chose life over death. After you choose to work for him G-Man puts you in a slow-time-warp (i.e., you are put into stasis) to call upon you when needed.

2002- The Portal Storms

Black Mesa has a huge ripple effect on the rest of the world after the events of Half-Life 1, as the Combine gradually open up portals world-wide, via its portal-network satellite. Aliens (from Xen) of all types are teleported into suburbs. Headcrabs crawl along the aisles of grocery stores while others teleport into swimming pools and homes. Utter chaos erupts on Earth. The freed Vortigaunts flee to Earth to escape the Combine, which are struggling to regain control of them.

A huge population shift occurs as people move into the cities, protected by soldiers and barbed wire fences, to escape the monsters. A feeling of safety comes over the people of Earth, as they can once again live normal lives within the confines of the cities, as the aliens continue to infest the outside world.

Meanwhile, the Combine prepare for an assault on Earth, assured that the required portals are in place. Now that Nihilanth's race have fled from the border-world to Earth, the Combine can forget about Xen and enslave both Mankind and Nihilanth's race in one fell swoop, on Earth.

2004- The Combine Invade Earth and The Rise of the Combine Overwatch

Using the established Xen-Earth portal network as transport gateways, The Combine launches a multi-pronged, all-out assault on the entire Earth, teleporting troops as well as drop-ships, gun-ships, and striders from Combine off-world outposts. Once there, the Combine uses the same technique that they used on Xen on the humans, building a super-army out of the combination of the DNA of the most dominant species on Earth (the humans) and Combine technology.

The primary Citadel is established in City 17. This enormous structure is home to the Earth based Combine control centre. Combine armies are produced here as well as vehicles and armaments. Combine presences are established in other cities around the world. (It is hinted that there may be other secondary Citadels around the world, linked by a network.)

While fighting each other, the humans and Combine also have the threat of Nihilianth's race. The freed Vortigaunts ally with the rebel forces, wanting revenge against the Combine. The headcrabs, being headcrabs, just attack anyone they can find. Other monsters find their place assaulting both Man and Combine.

The next stage of the Combine's plan takes root. Wallace Breen, still optimistic about the Combine takeover, is made the Administrator of Earth, as promised back in Black Mesa by the Combine. Breen surrenders Earth to the Combine, explaining that the Combine are here for good, to immortalize humanity. Even though he sees the corpses of fellow humans, he believes that the loss of life is inevitable in the transition period, as Earth joins the Universal Union. Breen formally "surrenders" Earth after 7 hours of combat between Mankind and the Combine. Breen being a human helps the Combine, too. He is a species-specific leader (Like Nihilanth) - this helps propagate the lie that the enslavement of humans is a good thing, and humans, seeing a human in power, can be more readily fed world-changing events that are not in their interest.

Most of the major population centres of Earth are destroyed. People move into the country, spreading out to avoid Combine capture. Small pockets of rebel fighters surface, but have to establish bases in un-safe areas in the country, where the Xenians have manifested themselves, finding niches in Earth's ecosystem. Still under the spell of the Combine, and ignoring the massive genocide, Breen views the building rebel force as a group of short-sighted troublemakers.

(iii) Cities renamed. The remaining populated areas are named City 1, City 2... City 17, City 27, etc and are placed under control of the Combine, who are establishing a huge presence on Earth. The United Nations in New York City is taken over and destroyed.

Wallace Breen takes residence in the top floor of the City 17 Citadel, attempting to quell the rebels. Breen attempts to console humanity by permanently making a connection between himself and it. He does by controlling the media. Huge television screens are erected in city centers. Newspapers, television, and other forms of communication are censored and their content is controlled.

Breen's message is simple: That humanity should not attempt in any way to cause friction in the transition period as mankind integrates itself with the Combine. He believes in order to join this Universal Union, Man will have to sacrifice a lot, but he still believes that the ends justify the means. He truly believes that joining the Combine will be positive to humanity, and tries to convert the rest of it to his point of view. After The Portal Storms, the humans are in such disorder that they can and will believe something like this.

Ruling by fear, the Overwatch assure to continue to protect human city centres from the outside aliens, and thus fearful humans continue to live in the cities out of fear for their families and themselves. The Overwatch's brutal reign begins.

The Combine's purpose with Breen is also simple. His purpose now is to prepare Earth for the Combine. His job is to eliminate any resistance to the Combine. Using controlled raids and a "civil-protection" force, Breen captures and converts any resistance to stalkers, human slaves. Additionally, the Overwatch attempt to re-enslave the Vortigaunts, with some success. The Combine's ultimate purpose is to convert all of humanity into stalkers, and all of the vortigaunts into the slaves they were before Gordon freed them.More important minds are taken to Nova Prospekt, where they are stored in containment and experimented on - the Combine want to get as much knowledge out of humanity as they can before they destroy it.

The Combine Overlord orders some transitional tasks, above and beyond Breen's power. First of all, the Overwatch enact a Suppression Field to prevent humans from procreating. (Previously, protein chains important to the development of an embryo were specifically blocked.) They do this so no new humans can be born, and that the humans left on Earth will be the final generation of them. They also put a biochemical in the water supply to make people gradually forget the past, and so they can more easily comply with Breen and the Combine - to forget why they hate them. Finally, the Combine begin to drain Earth's oceans. These tasks show that the Combine are preparing Earth for new residents.

2020- The Rebellion and The Fall of the Citadel

he Human Rebellion is Gordon's first official assignment, and his second assignment under the supervision of G-Man. G-Man pulls Gordon out of the slow-time warp for his assignment. Once Gordon is discovered, Wallace Breen makes his capture or death a top priority for Combine Overwatch officers.

Gordon continues to slip out of the Combine's grip and at Nova Prospekt, lands a huge blow against the Combine. This sparks a massive revolution among citizens, who begin a much larger rebellion than before. Chaos erupts in City 17 as Wallace Breen and the Combine Overwatch try frantically to end the spreading revolution, and the Citadel is put into full attack mode, with Combine soldiers flooding the streets. Vortigaunt refugees from Xen ally with the resistance, as they see the Combine as the greater threat. G-Man oversees Gordon's mission, assisting him where necessary.

At the end of HL2 you complete your assignment, by destabilizing the Citadel in City 17, the Combine throne on Earth. As a result, the Combine's communication network has been taken down, and the Combine forces are fractured and leaderless.

G-Man tosses his pawn back into stasis. He abandons Alyx, left to be incinerated by the Combine portal explosion. Gordon is now in hypersleep, as he has completed his job, and he is no longer needed. Or is he? It seems a group of purple Vortigaunts think otherwise. They warp in, rescue Alyx, and transport her outside in front of the Citadel. They pull Gordon out of stasis, and transport him to a location near Alyx. Both of these things happen against G-Man's wishes.

Meanwhile, the remaining Combine and Overwatch soldiers are hard at work at the Citadel. Since Gordon and Alyx destroyed Breen's reactor, the Combine on Earth have lost their primary method of communcation with their Combine leaders. Their plan is to use what is left of the Citadel's resources to send a last ditch distress signal to the Combine leaders, requesting for major reinforcements. In order to send this final transmission packet, the Combine will have to overload the Citadel's core reactor, setting off a chain reaction that will incinerate City 17. This will lead to the deaths of all of the rebel forces and evacuees of the city. The Combine also prepare the remaining Combine for escape via escape pods during the meltdown.

Why do the Vortigaunts pull Gordon out of stasis and place him just outside the Citadel? I believe they want Gordon to stop or at least delay the destruction of the Citadel. They want Gordon to stabilize the core reactor of the Citadel so that the rebel forces and the rest of the Vortigaunts can safely evacuate the city before it is destroyed.

Why doesn't G-Man like them doing this? The way I see it, G-Man wants that reactor to be destroyed as soon as possible and that transmission packet to be sent, at any cost. Why? Because it seems G-Man is trying his hardest to lure the rest of the Combine forces over to Earth. This seems like G-Man's plan from the beginning, the reason why he got Gordon to destroy the Citadel. This reason is to bait the rest of the Combine over to Earth so they can be fought on Earth, or so that G-Man could distract the Combine while he mounts an attack on the Combine's homeworld. The way G-Man sees it, hundreds of thousands of human and Vortigaunt lives will be lost in the destruction of City 17, but if that message is sent, G-Man could win an interstellar war. On the other hand, the purple Vortigaunts care more about the lives of the members of the Resistance and the citizens of City 17 on Earth than winning the war.

Unfortunately for G-Man, Gordon and Alyx do stabilize the core (or at least, for a few hours) to allow the Resistance to evacuate. However, this allows the Combine enough time to send their message, as well as successfully evacuate the Combine escape pods from the Citadel. You get to witness the Combine escape pods being loaded at the beginning of Episode 1 in the Citadel, as well as see them jettison from the Citadel at the very end of Episode 1. Click on the picture below to see the Combine escape pods up close.

Gordon and Alyx navigate their way out of City 17, into the countryside, just as the Combine plan goes into action and the final transmission packet is delivered, and the Combine escape pods are jettisoned. We do not learn if the transmission successfully reaches its destination. What happens next will be explored of course, in Episode 2. See the trailer for Episode 2 here.

So who is G-Man & what is his goal ? The official HL2E1 site calls G-Man a "sinister interdimensional bureaucrat." The way things are going, I believe that G-Man is an agent of an interstellar rebel alliance (assuming a human form), seeking to try to break down the ruthless Combine empire, an empire which I believe existed far before the events of HL1. This rebel force has incredible technology to be able to control teleportation in the way G-Man does. I don't think G-Man and his rebel alliance really cares about humanity all that much, but rather, they see Earth as a viable battleground to fight the Combine on, or a strategic way to divert the Combine's attention. Perhaps he realizes that Gordon Freeman is the only one who can defeat the Combine empire, and keeps him on call for this sort of thing. You have to remember, Gordon also freed a different race: the Vortigaunts. So this is the second big blow Gordon's struck against the Combine. NOTE: I do not believe that G-Man is Gordon Freeman from the future.