Anna Torv and Joshua Jackson Anna Torv and Joshua Jackson

Olivia has been kidnapped. Peter still hasn't found a way home. And David Robert Jones is running amok in both universes.

These are just a few of the problems the Fringe crew faces in this week's new episode, "The End of All Things" — which also happens to be the final episode for nearly a month. As Peter (Joshua Jackson) attempts to recover his lost love — new timeline Olivia (Anna Torv), to be clear — he'll come face-to-face with the man who once saved his life: the mysterious Observer known as September (Michael Cerveris), who will offer up a wealth of answers as to who the Observers truly are. Here are five teases from Friday's episode to whet your appetite:

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1. Which Nina is real? We'll be left guessing which Nina Sharp (Blair Brown) — the one who was abducted with Olivia, or the one at Massive Dynamic — is the real one from this universe. As you yell at your TV thinking you know who's who, let's just say hands can be deceiving.

2. Olivia's background, revealed: With Nina also abducted, we'll finally learn the story of how she raised Olivia and her sister — a huge contrast to original-Olivia's upbringing. And though Nina has been incapacitated to bring out an emotional side in Olivia, it's Peter who holds Olivia's fate in his hands.

3. David Robert Jones (Jared Harris) is back: The dastardly villain returns, and with him, a very familiar device that Fringe fans will remember from Season 1's "Ability."

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4. Observers, observed: We'll get a first-hand look inside the minds of the Observers, specifically September — though that's not his real name. We'll also learn exactly what they are and where (or when) they're from.

5. Peter timeline troubles: Why are the Observers so hell-bent on erasing Peter? It's not necessarily him that they're trying to get rid of.

Fringe airs Fridays at 9/8c on Fox.