Hola Fringe fans! I didn’t get to review last week’s episode because I was traveling, but let me just say this: it was a good one. People seemed to be really jacked up about “Firefly” and while I don’t overtly disagree with the enthusiasm, I think a lot of it had to do with the new airtime, the ratings and all that extratextual stuff that went into the overall aura.

Tonight’s episode “Reciprocity,” however, was flipping fantastic all on its own right.

For the most part this season has focused on Olivia and that’s absolutely been a great thing for the series. After season’s one messy perspective, season two cleaned up with more direct emotional stakes, particularly for Walter. But if Walter’s emotional state dominated season two and Olivia’s been the center of this season, the best run of Fringe has seen Peter in a more reactive sort of role. He actually says that himself in this episode. It’s not that Peter hasn’t been the lead dog in certain episodes or even across multiple ones; he was a crucial part of the greatness that was the second half of season two and he’s certainly played a sizable role in the battle between the universes. But because Olivia’s the true lead and Walter’s the emotional center, Peter’s usually serviced third. That’s fine, it’s not a major issue, but amid all the universe hopping, prophecies and other zaniness that has been this trio’s life over the past few months, the series has checked in on Peter’s emotional state the least.

“Reciprocity” rights those minor wrongs and in a big way. In a short period of time Peter found out he was from a different universe, discovered that his separation from his home universe might be the cause for all his current universe’s issues, learned he was being groomed for some sort of arranged marriage with a doomsday device, reunited with his real father, fell in love with a girl, continued that relationship with her inter-universe counterpart, discovered this unfortunate fact, watched Broyles’ doppleganger die and he still worked all the normal weird Fringe Division cases on top of that. In short, Peter’s had a rough freaking go of things. It’s perhaps not as devastating as Olivia’s entrapment and identity theft, but it’s damn close.

But because of his general disposition, we haven’t really seen much reaction from Peter in reference to these events. He’s certainly voiced legitimate concerns about the doomsday device, spoken his mind to Walter about the cross-universe kidnapping and expressed all sorts of regret to Olivia about their unfortunate circumstances, but we haven’t actually seen how Peter reacts to all these awful events in private. A few episodes ago, Olivia completely lost it in her apartment, destroyed her closet and bed and generally couldn’t take it anymore. We haven’t seen anything like that from Peter. He’s been a more concerned version of his stoic, mysterious self.

Here, all that stoicism and mystery gets peeled away and we finally get to see what’s happened to Peter’s psyche and not surprisingly, it’s in bad shape. When a bunch of shapeshifters who were on Fauxlivia’s records start showing up dead, the team races to figure out who the culprit is because they assume Walternate is using his extended reach to shut them up. But before long it’s pretty obvious that’s not what’s happening. Instead, it is Peter who is traipsing around in the shadows, killing the shapeshifters in hopes of using their data plates for information about Fauxlivia’s purpose, Walternate’s plans and anything he can find about the doomsday machine.

Peter’s never been afraid to get his hands dirty and there’s slight indication he’s probably done some harm in the past, but this is just super dark. Peter clearly has no pretensions about what he’s doing and he doesn’t appear to feel remorseful. However, as Walter notes after he discovers Peter killing the last shifter on the list, if his son didn’t feel like he was doing anything wrong, he should be able to tell Olivia, Astrid and Broyles the truth — which he is not. He might not feel too bad about killing killers, but Peter is smart enough to know that this turn towards the dark side isn’t necessarily a sign of confidence to those closest to him who might have some fears about what all this doomsday device nonsense has done to him. After being in control for all those years while Walter was locked up in the insane asylum, the rug has been pulled out from underneath him in the last year or so in a number of ways and the events of this episode present us with a Peter who is clearly trying to regain control, no matter what it takes.

What’s really interesting is that despite all the dark and twisty feelings Peter clearly has about his personal destiny, his relationship to Olivia seems to be the only thing keeping Peter in some sort of control. Though he tries to keep her from the possible humiliating information in Fauxlivia’s files, she reads them anyway and begins to come around to the fact that the two Ms. Dunham’s are nearly identical. There’s a reason Peter couldn’t tell them apart, Olivia barely can when reading her counterpart’s files. But now I’m wondering what would have happened to Peter had Olivia not started to come around? He’s clearly been doing some sketchy stuff in secret that he doesn’t want her to know about (perhaps even more than we know of), but will her affections pull him back or will the continued confusions between them push him further towards bad decisions that might seem useful at first.

Nevertheless, this was a fantastic episode with really tremendous performances from everyone on the cast. Like his character, Joshua Jackson is often the forgotten man in the lead trio, but I think this flipping of the switch in Peter points out how restrained of a performance he’s turned in over the series’ run. He can play Peter has the love interest, the mysterious handyman or the dark assassin, it apparently doesn’t matter. And as usual, both Anna Torv and John Noble had good moments, both with Jackson and on their own as the former continues to deal with re-establishing her place in this world and the latter hilariously ingested a substance meant for monkeys that possibly improves brain function and intelligence. I could watch John Noble act kind of like a monkey for hours upon hours.

At this point, I’m really intrigued as to how this is all going to come together. Massive Dynamic has put the doomsday machine together — it reacted to Peter’s presence — and apparently they’ve found nearly identical copies of the First People’s book while also discovering that William Bell was searching for them years ago. The series has been doing a fantastic job bouncing back and forth between Olivia/Fauxlivia and the universe war and Peter, the First People and this machine, but there isn’t quite enough information to even begin to discern how and why they come together to form a bigger picture. But I have absolutely no concerns about how the writers will pull it together, especially now that Peter has taken a more active role in his destiny.