Kleiner: A great deal, my dear. The blow you struck at Nova Prospekt was taken as a signal to begin the uprising.
Mere seconds after being whisked away by the Combine teleporter, Gordon and Alyx find themselves back at Kleiner's lab, but see no sign of the doctor himself. He promptly shows up to greet them from the other side of the teleporter room door, shotgun in hand, as if he wasn't expecting them to teleport into his lab at that very moment.
Kleiner explains that it's now been a week since the two of them teleported out of Nova Prospekt, and in their absence the Resistance went and kickstarted an uprising against the Combine. He adds that Eli is being held prisoner in the Citadel, but provides some levity by revealing that D0g managed to make it back to his lab, much to Alyx's delight. At that moment Barney makes contact with the lab via Kleiner's video terminal and informs him that he's setting up to launch an assault on the Citadel. Alyx tells him Gordon and D0g will go and assist him, while she stays with Kleiner and helps him find someplace safe.
With that, D0g leads Gordon out of the lab and onto the streets of City 17, which are now crawling with Overwatch troops. After fighting off a couple squads of soldiers and an APC, D0g is inadvertently separated from Gordon when a Dropship flies away with him hanging on to it, leaving Gordon to continue on by himself. Not long afterward, he finds himself at the plaza in front of the very same train station the G-Man inserted him at the start of his journey, just in time to see some rebels dismantling the Breencast screen there. The rebels are elated to see Gordon and are convinced they finally have the upper hand in the uprising with him back, and they follow him as he goes forth.
As Gordon travels towards the Citadel he clears out various Civil Protection checkpoints and outposts, and at one point assists in reconnecting a rebel supply tunnel. He eventually comes across an apartment block being used as a hideout by the Resistance, but is informed that it's no longer safe to hole up in because it's being shelled by the Combine.
After moving quickly through the now-infested apartments, Gordon is reunited with Alyx, who explains that she's now helping to disable Combine generators to weaken their control of the city. She locates another one of them in a plaza nearby and enlists in Gordon's help in taking care of it. Gordon and his rebel followers follow her outside, then proceed to hold the line against Combine reinforcements while she hacks away at the generator's outer defenses, after which Gordon is able to disable the generator with his Gravity Gun. Gordon and Alyx evade the overwhelming Combine presence through a gate as their rebel allies get cut down by gunfire, but their way forward to the rendezvous with Barney turns out to be impeded by a destroyed bridge. Alyx climbs up a building to try and scout an alternate route for them; she notices a path through the canal below but is ambushed by the Combine on the roof, knocked out, and loaded onto a Dropship bound for the Citadel.
On his own once again, Gordon descends into the canal and enters a labyrinth of maintenance corridors and sewers underneath the city, fighting off headcrabs and pursuing Combine troops all the while. He eventually makes it out of these corridors through a warehouse and finds himself back at ground level.
This chapter contains examples of:
- Antepiece: Hopper mines are first introduced in a fenced-off courtyard, where you get to watch some poor Headcrabs get blown up by them. The only way inside the courtyard is to use the Gravity Gun to remove a piece of sheet metal blocking a hole in the floor, beneath which is a large cluster of Hoppers; this design choice nudges you into using the gun to pick up and dispose of the Hoppers as intended. One of your fellow rebels cinches the tutorial by informing you that defused Hoppers can be set back down and used against the enemy.
- Involuntary Group Split: Recurs during this chapter, when D0G opens a Combine barrier then is carried off by a troop transport, then again when Alyx later scales a building to spot the means for much less monkey-like Gordon to progress by and is promptly captured by a Combine patrol.
- Rebel Leader: Gordon becomes a full-fledged Resistance leader the moment he steps out into the streets, as all the rebels he comes across are more than happy to fight by his side and take orders from him.
- Remixed Level: After leaving Kleiner's lab, Gordon passes through the apartment blocks and plaza from the very first chapter, which are now in ruins due to the ongoing rebellion.
- Roaring Rampage of Rescue: Gordon's journey to rescue Eli from the Citadel, Combine presence be damned, starts in this chapter. Alyx being captured and taken there as well only gives him an even stronger motivation to go through with it.
- Spark of the Rebellion: Gordon learns that his assault on Nova Prospekt was taken by the Resistance as a sign to kick off an uprising against the Combine.
- Year Outside, Hour Inside: Gordon and Alyx's seemingly instant teleporter trip back to Kleiner's lab turns out to have lasted a week in real time, much to the doctor's awe.
