In tonight's episode, we learn that whatever Abu Nazir is planning, he's planning something big. And while Carrie, Saul and the team have been successful lately by uncovering Brody's role and even recruiting him to be a double agent, Nazir now has something the CIA was very close to uncovering and taking possession of.
The box carted out of the tailor's store in Gettysburg looks big enough to hold a small nuclear sized weapon. And the good guys might have had it earlier -- Quinn only discovers the false wall moments before an armed team comes in and kills seven other CIA agents -- had Brody been upfront about what he knew.
But Brody, despite his plea deal, keeps a lot of things close to his vest. While he admits he doesn't know the man talking to Roya the journalist at the beginning of the episode -- in an incredibly tense, well-shot sequence that shows how the CIA tails a suspect -- he almost continues to hide what he knows about the tailor's death. (He, of course, doesn't implicate himself in it.)