Peter Weller guest-stars as a scientist who leaves dead people wherever he appears, and I do mean "appears," because he just suddenly appears in a train. By the time he's gone, they're all dead, and not in the usual way, but as though all the energy was just sucked out of them. The Fringe team investigates, and the trail leads them to Alistair Peck, a former MIT scientist working on some crazy (yet totally plausible, Walter figures) time-travel theories. The police get to him, but he just winks back in time again, back to the train again, only with his knowledge of what's going to happen, things play out differently, kind of like when you read a Choose Your Own Adventure book and make the wrong choice and wind up dead, so you go back to your last choice and go the other way? Anyway, the Fringers and the police close in again, albeit in different ways, and find out more information, figuring out that Peck is trying to jump back ten months because he's racked with guilt over the way his fiancée died, since they'd had a big argument.
Knowing a kindred spirit when he sees one, Walter tells him how to modify his equations so he can do it, but advises against it, since he himself once went to "the other side" to retrieve a loved one, and it hasn't exactly been ideal. In fact, Walter struggles with the guilt all through the episode, and Peck's not unsympathetic. He jumps back in time anyway, and reconciles with his fiancée -- just in time for both of them to be killed, which is pretty clearly what he figured was going to happen. He leaves behind a message for Walter -- a picture of a white tulip, which Walter had confessed to him was a sign of forgiveness from God that he prayed for, a confession that now didn't actually happen (although I think the likely consequences and effects of time-travel are glossed over slightly) -- which Walter receives after deciding against revealing his secret to Peter in a letter.
Back inside the train, the lights start flickering. The passengers look around, bewildered. Then, a few things happen simultaneously: the lights go out, the passengers are all dead (they haven't moved from their seats, but they are suddenly ashen, motionless, and their eyes are closed), and there's a man standing at the back of the car. That man is Peter Weller. Twenty-three years after the fact, I can't see him as anything else but RoboCop. I suppose it helps here that he's not wearing the suit.
He looks around the car (the only light is what's coming in through the windows), looking distressed at being in a car full of corpses, and goes to get off the train as it slows to a stop. The panhandler greets him with a "spare change?" as he gets off, but Peter Weller says nothing and hustles away down the platform. The kid gets on the train, and he's considerably more freaked out by all the dead bodies around him. As Peter Weller walks away, the kid starts hammering on the window: "No, please! Let me out of here!" Well, the door is right there, you wuss.
After the opening credits, we see Walter writing a letter. And it's not, as I assumed, a letter to some soft drink company advising them on the best way to improve their root beer formula. We can see a couple of sentence fragments: "Peter, I have struggled with this unimaginable secret" and "nothing I would not do for you." The phone rings, and Walter lets the answering machine pick up. I love the way that people in movies and television never use voicemail, because then we wouldn't be able to hear the message being left by the caller. It's Peter, figuring Walter is home and asking him to pick up. Several times, first by smilingly introducing himself as Walter's son, and then by reminding him which button on the phone to push. Peter's in the lab, looking like his soldering something.
Walter makes no move to answer, and Peter eventually gives up, and just tells him to get his kit together, because Olivia told him about an incident on a train, and Peter knows how much Walter likes trains, so he figures it would cheer him up.
Walter finishes up the letter and folds it in thirds and puts it in an envelope marked "Peter" and folds his hands and broods.
As the Fringe team strolls up to the train full of dead people, Peter asks Olivia if she's noticed anything weird about Walter. She says she hasn't, and Peter says his dad has been avoiding him all week, has stopped eating, and wouldn't even look at him in the car ride over. Most damning of all: Peter bought him a box of Peek Freans that he hasn't even noticed. "All week it feels like he's been enveloped in this ... sadness," he says. Olivia says she hasn't noticed anything, and you don't have to be able to read people expertly, as Peter has in the past claimed he can, to tell Olivia's lying, what with her swallowing and being unable to maintain eye contact with Peter. However, if he senses something amiss, he doesn't really show it.
On the train, Walter checks out all the corpses, sitting peacefully in their seats. He examines the bodies and thoughtfully gazes at a crucifix, hanging around a woman's neck, that appears to me made of copper wire wrapped around metal. Then he starts poking around her seatmate's leg, much to the annoyance of an FBI agent who demands to know what he's doing. He explains that he's checking their underwear, because people who die suddenly often vacate their bladders (and bowels). "Get off this train," she says, firmly, and Olivia has to step in to save Walter, who seems so downcast that he hasn't even snapped at this woman to go fuck herself. That's how depressed he is. Although, really, what's the woman's problem? Who did she think this guy was examining dead bodies in a crime scene that's been sealed off?
Anyway, his first theory is collective heart failure. Peter scoffs that all of them had a heart attack at the same time, and Walter half-heartedly suggests it was sympathetic. Contagious, like yawning. Man, even his crime-scene theories are just going through the motions! He doesn't even have any interest in arguing with his son.
Meanwhile, Olivia's looking around, and she asks Walter if his theory would suggest why all the lights are out in the car. Nope! Not only that, but Walter points out that there should be battery backup, unless it wasn't maintained properly.
While Peter grabs a BlackBerry from a dead woman's hand, Broyles comes to snag Olivia so she can talk to a kid who saw a six-foot brown-haired man in a trenchcoat getting off the train. "The man didn't speak to him or acknowledge him. He just exited down the stairs of the platform," says Broyles, who's awaiting word on the possibility of surveillance footage.
Back in the train car, Peter's still contemplating the BlackBerry before he stands up and exits, yelling for "Agent Dunham." I like the formality between them at the crime scene. After he leaves, a crime-scene tech notices an envelope by the feet of the woman Peter got the BlackBerry from. He picks it up and brings it to another investigator, "Rod," and hands over the envelope marked "Peter," and Walter manages to notice, whilst checking people for skid marks, and anxiously claims the envelope, just before Peter gets back on board with Broyles in tow, telling him that all the batteries on every electrical device on the train are dead. "All the cellphones, laptops, MP3 players. They're all completely drained of power," he says. Broyles asks Walter for theories, and Walter doesn't have any yet, but at least acknowledges that his half-assed "collective heart failure" theory is probably wrong. He adds that he'll need to take six or seven bodies back to the lab, and by this point, nobody bothers to raise an eyebrow at all the corpses that make their way back to Harvard, I suppose.
An agent gets on board, holding a surveillance photo of RoboCop, and the agents look at it and ask a bunch of useless questions like "Who is this guy?" and "How did he kill everything on this train?"
Later, back at the Harvard lab, Walter and Astrid are dissecting the bodies, much to Astrid's general disgust, who has finally realized she's not getting paid enough for stuff like this (i.e. cutting up dead bodies, baking cancer pizza, getting stabbed in the neck with hypodermics, etc.). Walter's saying that dying organisms struggle for their last breath, but these people, unusually, appear to have simply been switched off.
Peter comes in, cheerfully asking how things are going, and Astrid says it's not very good, as Walter asks her to take samples of a specific corpse's lung, brain and skin. Peter chirps, "Whatever it is, I'm sure you're gonna make sense out of it, Walter," and I love how Peter has gone from someone who loudly tells everyone that his dad and his dad's theories are crazy and ridiculous to the president of the We Love Walter Bishop Fan Club.
Walter is still seeming standoffish, so Peter comes right out and asks him if something's up, something that he wants to talk about. Walter says everything is fine, and then asks Astrid (whom he calls "Astro") to show him the previous cellular samples. After studying them, he calls them "extraordinary," and Astrid notices that the "ATP concentrations," whatever those are, are unually low. "Cellular process should continue for hours, even after death, but this man's mitochondria seems to have ceased functioning well before it should," says Walter, and even as he's asking Astrid t