Fringe went back to basics in “And Those We’ve Left Behind” with an episode mainly focused on the case of the week. But it was also the first episode that really took advantage of introducing a new timeline. I’ll offer some more thoughts about it after the jump.

In many ways, “And Those We’ve Left Behind” felt like a classic Fringe episode, with Peter and Olivia working a case together and Walter engaged in some wackiness in the lab. But here, Peter wasn’t really in the employ of the FBI; he was simply the most likely person to know what was going on a series of time slips, given that he claimed to be from an alternate timeline. So, Broyles and Olivia brought him in to investigate the weird goings-on.

This was a necessary development for the show. Though Peter is literally an outsider to this timeline, keeping him an outsider to the action forever wouldn’t have been sustainable. Bringing him into the fold and watching the other characters bounce off him seems like the most logical way to unify the stories of the multiple timelines. This all might have sat too close to Stranger in a Strange Land territory for some, but Peter wasn’t running around changing lives or telling everyone about the joys of Martian sex. His influence here was subtle, drawing Olivia ever-so-slightly out of her shell. In fact, Broyles and Olivia quickly took a liking to Peter and found that he fit on the Fringe team quite nicely.

But as well as Peter fit in with the others, he still felt like a stranger in this timeline. This week’s case was a nice reflection of that, involving an engineer, played by Stephen Root, who attempted to turn back time in a small bubble in order to go back to a point where his wife wasn’t suffering from dementia. Root was excellent here, perfectly playing the deep sadness he felt at seeing his wife’s mental condition, as well as the desperation that led him to create the time bubbles. The engineer felt as if he was a stranger in the time where his wife had dementia, and believed that the time when his wife had full control of her faculties was the “correct” one, until his wife reminded him that he should go on living his life instead of attempting to stay frozen in time.

There are two ways to interpret how this applies to Peter. The first is that Peter is a stranger in this timeline and needs to go back to his original one; he shouldn’t get too comfortable here. The second is that Peter shouldn’t attempt to get back “home” and should instead attempt to live his life by accepting the new timeline. It’ll be interesting to see which course Fringe takes, or if it will pursue a third option.

If there’s one problem this episode had, it was how quickly Broyles and Olivia came to trust Peter. At this stage, for all intents and purposes, he’s a Fringe event. The man just appeared out of nowhere, naked in the middle of a lake! Fringe Division has no way of verifying where he’s from or what he might be up to. That they would bring him in to investigate a case and then let him out of his cell to live in a home to which he has no legal claim was completely implausible.

But as implausible as all of this was, it finally drew Peter into whatever action is happening now. I look forward to seeing how Peter interacts with the rest of Fringe Division in the future and how he deals with slightly different versions of the people he used to know. It was heartbreaking to see how much he wanted to have Walter as his father and Olivia as his girlfriend again and how he was trying hard not to project his image of the people he knew onto the people in this timeline. It finally seems as if the old timeline indeed matters in this season of Fringe. That’s important, because as recently as the previous episode, I got the sense that the show was throwing three seasons of story out the window. Now that I know the old timeline will probably play a role going forward, for the first time this season, I’m genuinely excited to see what comes next on this show, and that’s exactly how I want to feel about Fringe.