Liz: "How would I fucking know?"
Um. Literally everything that has ever happened on this show.
Despite Harrison's "serious layers of encryption" we have managed to find terabytes of data on a hidden partition that is all about stalking this girl Abby Fisher. Liz figures out the connections pretty quickly, between Abby and her dad and also Harrison, and they go down the rabbit hole of how he was spying on her with her webcam, and emails, texts, and even her "mp3 collection"!
Liz: "So he is a stalker. Like legally that's what he is doing. Man, what kind of a world is it where even your 'mp3 collection' isn't safe?"
Fisher: "This is David Fisher, is this the FBI?"
Liz: "Yeah, is your daughter being stalked by a..."
Fisher: "Are you breaking up? Hello? Hello, Liz? Just kidding, the internet hung up on you."
Grid control! The whole city of Washington DC shuts down at just this moment, just like how the Skeleton Key works. The Post Officers spend a serious amount of time bumping around in the dark trying to figure out what happened before they figure out what obviously happened and then they're like, "We should go to David Fisher's house! I just hope cars still work."
Outside it is not really anarchy, mostly it is just dark. I assume in the hospitals people are croaking left and right, but since that doesn't have to do with Harrison Lee's teenage feelings, that doesn't matter this week. Somewhere Tom Keen is standing in the dark in a towel, having just been caught in the middle of flexing his muscles for himself in the mirror and talking in a German accent. Somewhere, Red Reddington is not even interrupted because his entire life is about redundancies and contingencies, so he just keeps putting together his cuckoo clock or whatever by the light of a generator that automatically kicked in. Somewhere, Mr. Kaplan is shaving a camel to make a coat for her favorite felon.
Aram: "Using black site technology and your NSA electronics, we can still track the iPad that is unleashing this havoc. Do you know its IMEI and the ICCID numbers? Or what those are?"
Liz: "Great, so he's in this five-mile radius on this map I guess."
Ressler: "Wait, how come the lights are all off?"