Agent Kashner's got two problems. One, he is an unwilling assistant in a brain autopsy, and two, Walter keeps calling him "Agent Casper." Astrid plays it cool as Walter lifts away a wedge-shaped section of Leeder's skull, and tells Astrid to call Peter before he's even finished extracting what he's found inside: a little rectangular computer chip with a long wire trailing from it. "Urg, I'm out," Kashner gags. And this isn't even the low point of the episode for him.

Peter gets Walter's call just in time for him to ask for a look at the body before it's loaded into the ambulance. Walter's telling him what he found embedded in the midbrain. "The thalamus," Peter guesses. Walter congratulates him on a sensible guess, and Peter calls Olivia over while Walter tells Astrid that the thalamus is the part of the brain that regulates sleep. Olivia arrives where Peter is groping the newest body, asking what he's looking for. "That," Peter says, showing Olivia the late woman's incision to match Greg's. I think the show kind of missed an opportunity here: a USB port in the back of the neck would be so much more Fringey, don't you think?

And after the ads, we're at Massive Dynamic, where Agent Broyles is having a meeting with Nina Sharp. This seems a little low-level for them, but I guess they needed something to do in this episode. Specifically, Nina is telling Broyles that the chip is a "brain-computer interface, or BCI." Well, of course it is. Furthermore, this one has a wireless transmitter. An unnecessarily freaky long-range shot from a camera that's slowly tipping over in the far corner of the room is used to show Nina confirming that it works on the brain like a pacemaker does on the heart, monitoring the sleep cycle and stimulating the thalamus to induce deeper sleep when necessary. She also gives Broyles the Massive Dynamic dossier on a Dr. Laxmeesh Nayak, a researcher in Seattle who's been working on stuff like this. "The man's a genius. We've been tracking him for years." Broyles thanks her and promised to inform the team. And that's it for Nina and Massive Dynamic this week.

Next thing you know, Olivia and Peter are at the good doctor's house, showing him photos of the two victims. He immediately recognizes them as his patients and asks what it's about. "Both of them recently committed homicidal attack and then...died," Olivia says with a weird smile. "As a result of what appears to be extreme exhaustion." Nayak is shocked, but not to hear about the chips found in their heads. That's because the two dead people were part of a study, 82 people strong. Olivia urgently asks for the names of the other subjects. What's the hurry? I'm sure they'll reveal themselves soon enough.