This week’s episode of Fringe, “Through the Looking Glass and What Walter Found There”, continues the search for the missing pieces to Walter’s machine. And with a 90-degree spin into a pocket universe, the living component needed to defeat the Observers is revealed. But does a warning of Peter’s grave mistake (from last episode) hint of a bigger threat waiting to be unleashed?

The story, like many in Fringe season 5, involves the Fringe team following Walter’s previously recorded videos, attempting to retrieve the parts needed in order to assemble a machine to defeat the Observers. Fortunately, that is where all similarities cease. Because while this episode’s adventure appears to be like many others we’ve seen in the passing weeks, a few welcome additions to the story has allowed Fringe to somewhat return to its series origins of mixing science and mystery to engage audiences, all while continuing to progress its overall goal.

Walter, knowing where to enter the pocket dimension, heads off on his own, leaving Peter, Olivia and Astrid to follow behind him. As Peter and Olivia enter the pocket universe with Walter’s camcorder, leaving Astrid as watch, the entirety of what was recorded is revealed, as Peter and Olivia realize that you can only see the parts recorded from the pocket universe whilst being there. Though this could sound like any episode of Fringe this season, what follows helps to set itself apart from the rest.

Instead of simply looking for an item to help in their battle against the Observers, the video reveals that it is actually a child Observer (from an old case) that they should be looking for – which helps to ramp up the intrigue for those watching. Additionally, because the episode itself contains a relatively simple plot (search and retrieve – even if they don’t), the story makes way for many nuanced character moments to shine, allowing Fringe season 5 to rid itself from the miniseries aspect it’s since been presenting, transitioning into something that more resembles the show in its previous season.

Even though Walter, Peter and Olivia are ultimately unable to find their needed Observer, they know he’s out there. What age will he be when they find him? That’s another question. Even so, the purpose of this episode was to provide some much needed exposition from Olivia, Peter and Walter about everything that’s happened in this season. Though successful to a point, more is always welcome – especially since Fringe season 5 does stem from a single episode in season 4.

As the episode comes to a close, fans receive a hint at what the biggest threat to come may be, as an Observer comments on Peter’s decision to become an Observer himself before being killed by a transporting Peter. And, as expected, the Observer leader is watching everything unfold from a distance, leaving fans with a question: Is Peter becoming an Observer a grave mistake?

Even though the Observers have played a big part in Fringe, we still don’t know much about them. Though we now know that a device in the back of their neck provides them with the abilities they have, we still don’t know what the Observers were like before receiving the implant.

Since the Observers are, for all intents and purposes, scientists from the future, one could question how much of their humanity is impacted by receiving an Observer implant – and whether Peter will be affected the same. Season after season, Peter has continuously been the center of any and all battles Fringe has presented, so it would be right to assume that he will be again. Could this be the last battle “the boy who shouldn’t exist” will be a part of?

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Fringe returns next Friday with “Five-Twenty-Ten” @9pm on Fox. You can check out a preview of next week’s episode below: