Back at the Harvard lab, a couple of agents are wheeling the body in, and they're a little bit unnerved by Gene's mooing. Anyway, Olivia gets a call from Broyles, who says he got a call from their military liaison (only he doesn't pronounce "liaison" with the same awesome sneer he did all through the Fringe pilot episode). "There's something to the rumours of military testing at Edina," he says, explaining that the army was there in the late '70s doing a series of classified experiments. Olivia asks if any had anything to do with metamorphic ability, and he says, "Not that I can tell; the Pentagon files have been almost entirely redacted." He says he's put in a call to the Department of Defence to find out more but he's faxing what they have in the meantime. He's actually faxing it right this second, and Olivia picks up some of the papers as she walks by. Meanwhile, Walter asks Astrid to help him with his kit. "I have to get to work, but there's a wonderful specimen in there for my favorite fan of four-winged fauna." Astrid's thrilled to hear it, because lord knows Astrid has never been able to shut up about lepidoptery.
Olivia, looking through the Edina info, tells Peter that the military testing done was called "Project Elephant," which makes them both think of Walter's song, so Olivia asks him if he was involved in any military testing in Edina. "Not that I'd recall. I'm sure I'd remember something as exciting as human metamorphosis," says Walter, because yeah, he has such a great memory for all the experiments he's done. He goes back to fumbling with the zipper on the bodybag while Astrid takes out the butterfly jar and, perplexed, says it was sweet of him to remember how much she loves butterflies but he forgot how much she hates moths. "What have you done to it?" he says, and Astrid is all, "Excuse me?" and Walter sees that yes, there is a moth in the jar, and he goes to Peter for confirmation that there was a beautiful butterfly in there: "It was an astounding creature! Nothing like this; its wing is deformed." And Astrid is all out-of-proportion pissed as she unzips the bodybag and tells Peter, "If that's your idea of a joke, it's really not very funny." Then she screams as she looks in the body bag. Joseph is all lumpy and misshapen again. "Oh my," says Walter. Now that's his idea of a joke.
After the commercial break, Walter tells Astrid that if she adds some wild thyme to the jar, it's possible that they can get the moth to transform back. Which sounds, frankly, like a lot of nonsense (it has a deformed wing, after all), but Astrid is still unfairly cranky when she snaps, "I'll believe that when I see it." I mean, Walter actually looks hurt.
Peter doesn't understand how it can be possible that the moth and the man transform in the same way, and Walter says they likely both developed the ability in response to the same experimental stimulus. "Why would the military be testing a butterfly?" asks Peter, the next logical question. Walter explains that the butterfly is one of the few creatures with the ability to abruptly change its body structure, which makes it a "wonderful alpha test subject."
Anyway, in examining Joseph, Walter finds it odd that there's no sign of histolysis or histogenesis, so nothing to suggest a metamorphic ability. "I just don't understand how he can possibly have transformed himself."
Olivia strolls in, letting them know that they haven't found a match on the fingerprints, but they got a hit on the truck's VIN (or, as Olivia calls it, its "VIN number"). It's registered to a Joe Falls with an old address for a house that had been torn down recently. But he was from Edina.
So it's back to the diner with the sheriff, who says Joe Falls worked at the mill, still does odd jobs now and then. Olivia manages to not say: "Correction: still did odd jobs now and then." He asks if "that thing" that tried to run Olivia off the road was him. Olivia says it's possible, but there wasn't a photograph on his file so they couldn't make a positive ID. She asks if the sheriff knows where Joe lives, and the sheriff says the last he'd heard Joe'd moved to the outskirts of town (it's worth noting here that in the establishing shot of Joseph's house there was a neighbouring house a lot more like a regular residential neighbourhood than what you think of when you think of the outskirts, especially in a small town). He couldn't say where, but he's happy to ask around for Olivia, who also wants to have a look at the town records to see if they can find a last known address or photo so they can ID the guy. The sheriff says he'll take them over to the town hall.
Back at the lab, Astrid's finished the analysis on the blood sample he gave her on the moth. Turns out it had a genetic disorder: "Ah, germline mutation. Just as I thought. This man has the exact same disorder," he says. Astrid asks if that's what he thinks lets them transform. "No, the mutation is what makes them deformed. I have no idea what makes them transform," he says. But he's got the strange feeling he's seen this mutation before. And then he starts humming Carmen, and Astrid starts whining about that, but of course now it triggers the memory that he worked on Project Elephant because OF COURSE HE DID, and then he puzzles out the song's meaning. Well, Astrid does -- after writing the words down she asks if "Harkness" means anything to him, and he says it's a library at the law school and then clues in that the song is a mnemonic and they haul ass to find out what's at the library.
Over in Edina, Olivia and Peter are coming up with sweet nothing as the entire F-section in the tax records is gone, suggesting that someone stole it. Olivia decides to check the federal records: "If you lived here, you must be on the census."
Over at the Harkness Law Library, it's all started to come back to Walter, which is fortunate, because I don't see how he would otherwise have remembered to unscrew a metal grate near the bottom of a bookshelf. While he's doing that, Astrid asks him what happened in Edina; he seems like a different person since he got back. Fits in with the theme! Walter says he's always found work to be restorative: "When Peter was sick, it was the only thing that kept me going. Amazing how it heals the soul," he says.
He's finally unscrewed the grate, the purpose of which in this part of the bookcase is beyond me (and considering how old this bookcase looks, it's lucky there haven't been any renovations done), and he pulls out a box of Devil Dogs, and he gets all excited, and you'd be forgiven for thinking that it's just a box to hold whatever Walter has stashed, but no, it's an old package of actual Devil Dogs that Astrid takes from him, promising him that they can get a fresh package. There's another box in the bookcase, this one containing files and pictures -- of people with grotesque facial deformities, just like the man in the lab, Astrid unnecessarily explains for us. "I understand now," says Walter.
Back in the town hall record room, Peter and Olivia haven't found anything on Joe Falls in 1990 or 2000. Peter asks what the current population of Edina is, and Olivia rattles off 1,943, since it was on the sign, which I guess makes Edina like the only small town to keep that current. Peter points out it's strange that between the years of 1990 and 2000, seventeen people died, forty-seven people were born. That's the only change in the population; i.e. no one moved in or out.
Olivia's cellphone rings. It's the sheriff, so Olivia tells him section F of the tax files is missing. The sheriff says he may know who's responsible, and explains that the "local tax collector" said Falls moved out to the