Everything old was new again as Fringe returned to our screens last night with an all-new history following the removal of Peter from the timeline. No wonder that we have five questions about "Neither Here Nor There."

What Has Changed?

It was never explicitly stated in the episode, but the idea that Peter Bishop has never existed - as stated at the end of the last season - doesn't necessarily seem to be true; Walter's comment about some people "dying twice" would suggest that both reality's Peters did exist, but that Walter wasn't able to save the Peter that we knew this time around. While Olivia explained that, in the new history, she was the one that checked Walter out of the mental asylum, little else was revealed about what has changed in this rewritten timeline, but things definitely are different: This Walter apparently never leaves the lab if he can help it, sending Astrid out to crime scenes with a camera, and sleeping in the lab, which raises at least one question for longtime viewers: Is he still in charge of Massive Dynamic? That is, of course, if Massive Dynamic still exists...

What Do The Observers Want?

For three seasons, we've had hints of the agenda behind the Observers' actions, but last night's episode was particularly frustrating on that subject: their official agenda seems to include preserving the new timeline, even if it means eliminating people from ever existing... but how do they know how to do that? And why are they immune to time being rewritten?

Why Does Peter Still Exist?

We saw him flicker in and out of existence once ourselves, and he's apparently appeared twice to Walter - in a way that, just possibly, could convince Walter that he's going mad again, given enough time - but... why isn't Peter gone? There were enough references to "holes" in people's lives or things being wrong throughout the episode to suggest that time hasn't been rewritten entirely successfully, so is Peter's survival part of that, or vice versa? If Peter somehow had the power to fuse realities together, could he somehow be immune to other cosmic laws - and if he is, how long before he forces himself back into full existence?

Where Do The New Shapeshifters Come From?

Given both Fauxlivia's reaction to being told about the new shapeshifters and rules of basic dramatic tension, it doesn't seem as if the new shapeshifters that appeared this episode - And am I wrong, or was the shapeshifter identification out of nowhere? Was there any evidence that would give Walter that impression for sure, or are we simply meant to assume that it's a sign of his own paranoia? - are necessarily from the alternate reality. If they're not, then are we about to uncover a third reality preparing to go to war with "our" reality? Or has the rewriting of time and fusing of realities had the side effect of creating all manner of new creatures with agendas of their own?

Why Is Lincoln Lee So Important?

This is the third time Lincoln has been introduced in the show; he was the leader of Fringe Division in the alternate reality, and then we met "our" Lincoln for the first time last year - a meeting that, according to the Observers, was rewritten out of existence by Peter's removal from the timeline. So what to make of the fact that he reappeared this time around? Just as Olivia had a connection to Walter that she wasn't aware of, initially, is there some link between Lincoln and Fringe Division that no-one knows about yet? Is it coincidence? Is Lincoln just similar enough to Olivia at the start of the show - Her exposition about the way in which she joined Fringe Division in this new version of history underscored that, surely? - that it's suggested that Fringe Division needs that dynamic (with Olivia as the new Peter) to work?

Overall, it was a strong return for the show, if a frustrating one - I want to know what has changed in time! Is Charlie alive again? Where is Massive Dynamic? But, as Olivia said, sometimes answers just lead to more questions. But then, questions are what we're all about here...