After giving us a history of certain Paris streets (there's a reason this book is so long), Hugo takes us to a bar scene in which the ABC dude named Grantaire gets stinking drunk while there's fighting going on outside.
He seems a lot more concerned with drinking than he does with changing the world. But you're always going to get these kinds of people during times of revolution—people who just want to sit back and enjoy life without getting into any trouble.
They head outside the bar for a bit and see their buddy Courfeyrac walking past, heading off to build a barricade. But they invite him to build a barricade just outside the bar, and it turns out to be a pretty good idea, since the street is in a good strategic location.
The leader of the ABC gang, Enjolras, eventually shows up and get down to some more barricade building. Grantaire keeps drunkenly offering his help, but Enjolras looks down on him and considers him a fool.
Soon enough, Gavroche starts helping out. He keeps asking Enjolras to find him a pistol that works, but Enjolras tells him to be patient. Gavroche ends the conversation by saying that if Enjolras dies, he (Gavroche) will take the dude's pistol. Bloodthirsty little guy!
Once the barricade is built, the men have nothing to do but wait for the army to come and attack them. It's a weird plan, considering that they're the ones who want to take over the Paris streets. But it sounds like none of them really thinks they'll conquer Paris. They just want to show their defiance as part of a more long-term battle for the souls of Paris.
While folks are waiting inside the bar, one of the new recruits for the revolt gets himself a musket and sits down with it, taking in the scene around him.
Meanwhile, Enjolras asks Gavroche to sneak out and check what's going on in the streets. Before he leaves, though, Gavroche nods toward the stranger sitting down with the musket and says that he is none other than Inspector Javert from the police. He's a total narc who's gone undercover to infiltrate the revolution!
Just like that, the folks from the ABC Society seize Javert and tell him to prepare for death. Gavroche—who's nothing if not single-minded—asks whether he can have Javert's musket once the man is dead.
Meanwhile, a dude named Cabuc is outside in the street. For strategic purposes, he wants to get into the house of one of the men in the neighborhood. The neighborhood man sticks his head out his second floor window and says he won't open the door for anyone, so Cabuc shoots him in the head. Enjolras is so disgusted by this behavior that he executes Cabuc on the spot.
We find out later that this Cabuc was actually a famous criminal in disguise.