Back at Harvard, Peter readies Roy for the operation by merely asking if he's got any allergies or drug use. Nope to both. "This all checks out. Strap 'em down," says Walter, freaking Roy out a bit, and Astrid tells him everything's going to be OK. And she knows that how?

As she straps him down, Astrid really runs up her line count for the series so far, chatting with Roy about how great it is to know he's not crazy, or whatever. No, it must be so much more reassuring to know that he's back in the hands of the crazy doctor who's RESPONSIBLE FOR WHAT HE'S GOING THROUGH, Astrid.

Over in Cambridge, Olivia and Peter are wasting time searching for the whatsit together when they should be splitting up. But it wouldn't give them the chance to blather at each other, with Peter explaining that he and his mom moved after Walter was institutionalized. Olivia asks where his mother is. "That's a story for another time," he says. He'd rather talk about why Olivia got into law enforcement, and if, since the psychological profiles of cops and criminals are almost identical, if she ever considered a life of crime. "No dental," cracks Olivia.

They're having no luck finding the magnetic neuro-stimulator, until Peter remembers a hidden compartment in a wall that his mom had covered off because he used to hide in it the time. He uses his knife to pry off some paneling, and finds a dumbwaiter with some old papers.

Back at the lab Walter is preparing Roy for surgery and brushing off the poor guy's feeling that Dr. Bishop seems familiar. Olivia and Peter stroll in, bearing a briefcase with Bishop's device, which kinda looks like a coil of Christmas lights. "This brings back memories," he says. "Of what?" asks Peter. Of a lifetime, Peter. Shit. Proust wrote hundreds of thousands of words when a glimpse of a magnetic neuro-stimulator caused memories to come flooding back.

Roy's strapped in now, and the device is positioned on his head, a metal headband holding it in place. There are holes in it. Walter is holding a drill. Walter is saying something about "intercranial penetration." The music is swelling ... and the tension is broken by a couple of idiot students asking if this is Poli Sci 101. "Not remotely," says Olivia.

Well, back to the matter at hand: DRILLING INTO ROY'S HEAD. There is blood dripping down his face. Walter tells Roy he believes there are metal clusters in the visual centre of his brain, and he's going to try to move them to the part that processes sound. Yeah, sounds solid, Walter. Peter starts showing Roy pictures on flash cards so Roy can describe any sensations. A horse. A picture of a car gives him trouble -- he says it feels like he's tasting gasoline. "We've reached the gustatory cortex. We're getting close," says Walter, quite pleased. Next up is a picture of a beach. Roy identifies it but says he doesn't feel anything (except a little scared after this annoys Walter). As usual, in scenes of pseudo-science, the key is to turn up a dial, but suddenly Roy starts speaking Latin. He says he can hear voices. Yeah, but actually speak the Latin just because you're hearing it? In an incredibly fortunate stroke of luck, Astrid was a linguistics major, so she translates the Latin to mean something's happening in an hour, an exchange at south station.