After weeks of hinting at the subject of time-travel, last night's Fringe on Fox took us into the future, and dropped more than a few bombshells about what's been going on in our present. No wonder we have questions about "Letters of Transit."

I think we can all agree: This was a wonderful episode, if one that came completely out of left field, seemed oddly disconnected to where the storyarc from this season has been headed, and was strongly reminiscent of Dollhouse's "Epitaph" episodes, which may not be the best thing considering what happened to that series. And yet... There was so much to deal with this week. For example...

Why Did The Observers Take Over In 2015?

Okay, so we're told in exposition that the Observers had ruined the Earth's environment by 2069, and so were making trips back in time to prepare to take over the former world and create a new society (Shades of Terra Nova). But… why 2015? It's clear that that wasn't the date when people became aware of the Observers, because Simon said that his family were members of the resistance before The Purge, so presuming that the Observers made their existence public before The Purge, what was so special about 2015 that prompted them to take over the world?

(Also, again: How important is Peter to this? The Observers had wiped him out of history, which suggests that his very existence was important - and then, his non-existence as important - so does his being awoken in 2036 mean that his presence was going to turn the tide?)

What World Was It?

Between the Fringe Division logo, the use of Amber and the Fringe headquarters… That was all the alternate Earth, wasn't it? Did this episode happen on that Earth, or does "our" Earth take a turn or several towards the alternate at some point in the future? That Walter and Peter were both present doesn't really skew things one way or another, considering the number of times they've crossed over in the past - Similarly, Etta's presence could just mean that she was raised on the alternate Earth, perhaps. But was this Earth-1, Earth-2 or another Earth altogether? Was this a merged version of the two Earths we've been following all this time?

(Another reason why I think this might be the alternate Earth - I am, for some reason, convinced that the Agent Broyles we saw was Colonel Broyles, from the alternate Earth… Something about him, and his uncertain loyalties, just gave me that impression.)

(And while I'm parenthesizing: Was that really our Walter, or Walternate? After all, when his brain had regenerated, he definitely seemed like Walternate, and knowing that William Bell was trapped in amber means that the voluntary lobotomy didn't have to have taken place in the show's past - it could still be something to come from our contemporary point of view…)

What Happened To Olivia?

"After what he did to Olivia… Even you couldn't be that compassionate," said Walter when explaining why he abandoned William Bell to Astrid. Earlier, too, Nina Sharpe had said that when the Fringe team had last saved the world, they did so at a terrible cost… Both references to back up the idea that Olivia has to die in order for everything to turn out okay, as suggested by September. But… If Etta is Peter's daughter, doesn't that mean that she's Olivia's daughter, too? And neither Olivia is pregnant yet, as far as we know, so she would apparently live on past the finale of this season… Not to mention, there's nothing to tie what's going on the main storyline with William Bell (yet), and if he bears responsibility for what ultimately happens to Olivia, we must be some distance away still… Right?

(Also: The reference at the top of the show to Etta being something unusual - She had her mother's powers, perhaps? Or she's a Cortexephan baby, and that's important somehow…?)

Where Has William Bell Been All This Time?

I admit it: The appearance of William Bell in amber caught me by complete surprise, and that's despite my wondering what his story is in the rewritten timeline at multiple times this season. Was this just something thrown in to blow our minds, or a hint about what's to come in the last couple of episodes this year?

What Happened To September?

Another throwaway line from Walter suggested that a dramatic fate awaits the friendly Observer… but it was so vague that we can't tell if it was a bad fate or a good one? Or, perhaps, something that is determinedly vague on purpose (He disappears?). Should we be watching out for hints in September's actions and fate in the next few episodes that could give us more understanding about his this storyline will play out? For that matter, will we ever see anything or anyone from 2036 ever again?