So Broyles tells the gang about the machine activating itself, adding: "It appears our assumptions were wrong," which is pretty much the case every week, and Walter starts putting the pieces together when he finds out that the machine started up just before the vortex appeared. "And if it's the end of the world, this is just the beginning," he says, gloomily.
But I guess that's no reason not to try to prevent it, so our heroes are now back at Harvard working on the problem, although Peter grouchily says the information they have is useless, since they'd been working on the assumption that he was the sole power source for the machine. Olivia points out that the machine responded to Peter, and Walter -- finally showing a little spirit -- says he might have a theory. He shows them a printout of the doomsday device's magnetic field, which looks vaguely umbrella-shaped, a kind that he's seen only once before: on the typewriter that Fauxlivia used to communicate with the other side. "Quantum entanglement!" says Peter. Sigh. It always comes back to quantum entanglement, doesn't it? Total television cliché. Just once I'd like to watch a television show that didn't trot out a "quantum entanglement" plotline.
Olivia figures out that means Walternate activated the machine over there, which Walter says would have sparked a "sympathetic" response over here. "It makes sense," he says. Sure it does! When you consider Fringe plotlines, the only possible response is "That makes sense!"
But there's not a whole lot of time for glee at the breakthrough theory, because Astrid relays some sobering news from Broyles: three more incidents -- colonies of bats above the New Jersey turnpike, mini-quakes in Florida, and in Newton, 30 acres of woodland completely decimated -- all organic life just dead and desiccated in a matter of hours. "The blight," says Olivia. Walter, being a total downer again, says he expects the events will increase exponentially, and there's no way to stop it. "He's won. Walternate's won," he says, a shining can-do spirit that's sure to inspire the rest of the team, none of whom says anything to contradict him.
And we go back over to Earth-2 where Fauxlivia is taking her son out for his first walk -- he's three weeks old, so I assume the rapid growth was halted somehow upon delivery. She's with the nanny? I assume? Which is fortunate because Fauxlivia gets a page alerting her to a Fringe event on Liberty Island, and she leaves her son with the woman who says she'll keep him safe while Fauxlivia keeps the rest of them safe.