What is the Vault and how did G-Man end up there?
Alyx and Eli Vance spend much of the game thinking the strange Vault hanging above City 17 is the location of some kind of Combine superweapon, but the story slowly reveals the Vault’s true purpose. It’s not a superweapon meant to crush the resistance fighting the alien occupation of Earth but a prison meant to keep someone very important trapped inside.
The Vances surmise it’s Gordon Freeman, the hero of the Black Mesa incident who’s not been seen in years (he will later return in Half-Life 2). Alyx decides to reach the Vault and free Gordon, but what she finds inside the Vault is beyond what she could have expected. Inside the Vault is what seems like a simulation of City 17 itself that’s unstuck from time and space. Rooms turn upside down, objects float in the air unperturbed by the laws of gravity, and doors lead into other places that don’t make any physical sense. This is the first clue that the prisoner in question might not be tied to the laws of reality as we know it.
When Alyx reaches the cell at the center of the Vault and opens it, she’s surprised to see the G-Man, the supernatural being first introduced in the original Half-Life as a recruiter for an unknown employer who often intervenes with the events of the story. At the end of the original game, for example, the G-Man — who is always dressed in a blue suit and carries a black briefcase — “hires” Gordon Freeman to work for him. In the Half-Life 2 finale, the G-Man pulls Gordon out of the action just as he accomplishes his mission, leaving Alyx to die and putting Gordon back in stasis until his services are needed again. G-Man will interfere in a similar way in Half-Life: Alyx but we’ll get to that in a second.
How did the G-Man end up in the Vault? It’s never directly addressed in the story, but there’s a more intriguing question to be asked here: When was the G-Man put in the Vault? After all, the G-Man can easily travel through time and space and the Combine has access to otherworldy science beyond the laws of time and physics. Could he have been captured after the events of Alyx? The G-Man’s preoccupation with the end of Half-Life 2: Episode 2 could mean that he was captured after the Vortigaunts interfered with his plans and freed Gordon in Episode 1.
During Episode 2, the G-Man appears to Gordon to tell him that he must see Alyx safely to White Forest, the Resistance base where the final act of the game takes place. G-Man reveals that he can’t directly interfere because he’s been forced to “abide by certain restrictions.” In the context of the game, the player is led to believe that the Vortigaunts are keeping G-Man from manipulating Gordon. But could the “certain restrictions” actually involve the Vault? Timey wimey, indeed.
