Location  >  Section 1 - Saga Timeline

eXTReMe Tracker
The Timeline of Events in Half Life History

This timeline goes over all the major events and plot points of the saga, from before Half-Life 1 to the end of Half-Life 2. The HL1 manual indicates that the Black Mesa incident occurred on May 5, 200-, implying by the "-" that the incident could take place during any year during the decade. For simplicity's sake, I assumed it happened in the year 2000 and went from there.
Gordon's Sleep Cycle
Major Events

The Retreat to Xen


- Combine Empire Invades Nihilianth's Homeworld

- Long struggle ensues

_ Nihilanth's Race Flees 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 (who is not necessarily a Vortigaunt). 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 dimensions. 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 race that Nihilianth commands, 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 and his people fight 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, Arne Magnusson and Issac Kleiner, crystals are retrieved from Xen, and organisms are analyzed. Research is developing.

Black Mesa's chief competitor for government funding, Aperture Science, also develops its own Portal technology parallel to Black Mesa onboard its many research facilities and enrichment centers, including the Borealis, a research vessel. One day, after what seems to be a severe mishap, the Borealis disappears completely off the face of the Earth, taking all passengers and crew with it. GLaDOS, an artificial intelligence program at Aperture Science, is made operational for the first time at one of Aperture's enrichment centers.


Gordon is put into stasis

1.2. The Resonance Cascade


-- (i) The Resonance Cascade (Triggered by GMan)

- Combine Empire Notices

- Nihilanth defeated

- Black Mesa destroyed

- Gordon survives

- (ii) Gordon is Hired

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

(i) GMan Orchestrates The Resonance Cascade, "GMan", a very mysterious figure at Black Mesa, whose motives seem to be independent of both humankind and of the Combine, triggers a resonance cascade within the Anomalous Materials sector of the Black Mesa complex, by bringing in a specific test sample to be used. His selection of this hazardous material is masked by a system crash, to cut out formal communication between scientists. The resonance cascade rips open space-time and forms a portal between Earth and Xen. Nihilanth's race sees the dimensional fissure as an escape route. Of course headcrabs and other life trapped on Xen decide to hitch a ride to Earth, for the fun of it. Black Mesa becomes chaos, as the Hazardous Environment Combat Unit, a United States Marine Corps Special Forces division, is brought in to quell the results of the Resonance Cascade, including the elimination of all humans caught in the cross-fire.

This resonance cascade is so immense in nature, that the Combine Empire notices it, turning their interest to what is happening on Earth.

One man in a HEV suit becomes of great interest to G-Man during the incident. 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.

Eventually Black Mesa is destroyed by nuclear detonation (noted in OF). Several survivors exist, including Wallace Breen, Black Mesa's former administrator; Barney Calhoun, a security guard; Dr Issac Kleiner, a prominent scientist at Black Mesa; Dr. Arne Magnusson; Dr. Eli Vance; and of course, Alyx Vance, Eli's daughter. Alyx is of particular interest to GMan

(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.

Gordon not aging

1.3. The Portal Storms


- Storms begin

- Population shift to urban areas

- Combine set plans for invasion

Unfortunately, though Black Mesa has been obliterated, Earth has yet to feel the brunt of this disaster. "Portal Storms", a seeming side-effect from the resonance cascade, form a dimensional rift between Xen and Earth. These Portal Storms spread outside the confines of what is left of Black Mesa and throughout all of Earth, providing temporary, chaotic, and destructive links between Xen and Earth. 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 use these storms as a ticket out of Xen and onto Earth, fleeing from the Combine.

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 alien species continue to infest the outside world. Vast networks of ant-lion nests are formed throughout the Earth's crust, housing millions of new species.

The Combine, who have been keeping an eye on Earth since the resonance cascade, finally decide to take action. They plan on taking the Portal Storms to their advantage and use them as a method to mount an invasion on Earth. 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.


Gordon not aging












1.4. The Combine Invade Earth

Attack launched

- "Portal Storms continue"

- Combine force storms wider
- 7 Hour War begins

- Overwatch soldiers created, citadels delivered

-7 Hour war Ends
- Breen made Administrator of Earth

- Population centers destroyed

- Events of 'Portal' take place

Forcing space-time and the portal storms wider open, The Combine launches a multi-pronged, all-out assault on the entire Earth. They teleport troops as well as drop-ships, gun-ships, and striders from Combine off-world outposts through the Portal Storms, and onto Earth. 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 center. 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, "made" optimistic about the Combine takeover, is appointed the Administrator of Earth, acting as a puppet for the Combine. How he is selected for this role is unknown at this time. Breen's first act is to surrender Earth to the Combine, explaining that the Combine have arrived for good, to immortalize humanity, convinced by the Combine that the loss of life is inevitable in this 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 - this helps propagate the lie that the enslavement of humans is a positive step forward, and humans, seeing a human in power, can be more readily coerced into their new lives.

Most of the major population centers of Earth are destroyed. Those still alive 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.

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. [ screenshot, from Eli's lab ]

Meanwhile, all scientists have evacuated their facilities at Aperture Science, including their main enrichment center. The events of Portal take place. 1 The 'Aperture Science Hand-Held Portal Device' is inadvertently released into the wild, however, it is not known what becomes of it.


Gordon not aging



1.5. Rise of the Combine Overwatch


- Control of media takes place

- Nova Prospekt established as "storage and experiment area"

- (iv) Civil Protection established

- Transitional Tasks


Wallace Breen takes residence in the top floor of the City 17 Citadel, under the close counsel of the Combine, 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, mankind 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 centers 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 an eventual total Combine migration. 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 [for definition, see Expanded Info section], 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. All of these things are leading to a drastic change in the purpose of humanity - it is about to become a slave race.

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. (In particular, 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.

(iv) Combine Civil Protection Unit established - See Expanded Info

Gordon wakes up

1.6. The Rebellion


- Gordon makes his return
- Lands blows all over City 17, and at Nova Prospekt

- Major Revolution begins

The Human Rebellion is Gordon's first official assignment after Black Mesa, 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, maintaining full control over Gordon, oversees his mission, assisting him where necessary.


Gordon is put back into stasis, and then pulled out again by a group of Vortigaunts



The Vortigaunts take GMan's place as Gordon's watchover

1.7. The Fall of the Citadel


- Citadel destabilized

- Citadel temporarily reestablished by Gordon and Alyx

- Combine jettison, prepare Citadel for last-ditch delivery of distress signal and creation of super-portal



- Gordon and Alyx navigate their way out of City 17

- Combine escape pods successfully jettison, attempt to deliver distress signal

- Citadel explodes, destroying the majority of City 17


-Super portal successfully opened and transmission packet sent

Super portal shut down by rocket


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.

GMan tosses his pawn back into stasis. Gordon is now in hypersleep, as he has completed his job, and he is no longer needed. GMan is about to warp in and transport Alyx when he is intercepted by a group of Vortigaunts. 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 GMan's wishes. The Vortigaunts have in effect taken control of Gordon, blocking GMan from intervening in Gordon's adventures. GMan has to resort to kindly asking Gordon to protect Alyx when the Vortigaunts let their guard down to save her life in Episode 2.

The Combine on Earth have lost their primary method of communication with their Combine leaders. In a last-ditch effort, they decide to destroy the Citadel in the creation of a high-energy "super-portal". In conjunction with the creation of this super-portal, the Combine need to send a transmission packet back to their homeworld detailing to their forces how to access it - what amounts essentially to a high level reinforcements request. This process 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 GMan like them doing this? The way I see it, GMan wants that reactor to be destroyed as soon as possible and that transmission packet to be sent, at any cost. Why? Because it seems GMan is trying his hardest to lure the rest of the Combine forces over to Earth. This seems like GMan'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 GMan could distract the Combine while he mounts an attack on the Combine's homeworld. The way GMan 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, GMan 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 GMan, Gordon and Alyx do stabilize the core (or at least, for a few hours) to allow the Resistance to evacuate. Though, in the end, this allows the Combine enough time to send their message, as well as successfully evacuate the Combine escape pods from the Citadel, in a stunning discharge of raw portal energy, leveling City 17. These escape pods are dispersed all over the countryside surrounding the remains of City 17. As a result, the immense super-portal is now operational and is awaiting the opening of another dimensional gateway from the Combine side.

Alyx and Gordon manage to secure two transmission packets from the Citadel. On the first packet are contained the exact coordinates and instructions for the operation of setting the super-portal as a gateway to send troops. The second packet is more intriguing- exact coordinates and blueprints depiciting the location of the missing Borealis freighter. On board is believed to contain a portal technology much more advanced than Black Mesa's.

Despite sustaining a massive attack, aided by a code from the transmission packet, the rebel forces manage to launch a rocket, which in concert with the satellites launched over 20 years earlier during the resonance cascade, is able to shut down the super-portal. The Combine is held at bay, for the time being. However, as Gordon, Alyx, and Eli (unfortunately) learn, the hatched Combine Advisors are still roaming the countryside, feeding on the very rebels that are trying to take them down.

What happens next, will of course, be shown to us in Episode 3.

So who is GMan? Visit the Extended Information section for more.

1 - The date that the events of Portal take place aren't certain. We do know that GLaDOS says to Chell: "Are you trying to escape? [chuckle] Things have changed since the last time you left the building. What's going on out will make you wish you were back in here. I have an infinite capacity for knowledge, and even I'm not sure what is going on outside. All I know is I'm the only thing standing between us and them. Well, I was. Unless you have a plan for building some supercomputer parts in a big hurry, this place isn't going to be safe much longer." This implies that the game takes place during the Portal Storms or afterwards. Read more about Portal on the Wikipedia page here.

Want some more information on specific elements of the Half-Life Saga? Visit the Extended Information section.

Have some unanswered questions? Continue on to the FAQ section.