Where's Peter Bishop? It's the question that has plagued the 'Fringe' (Fri., 9PM ET on FOX) marketing team all summer. In the Season 3 finale, he sacrificed his very existence in an attempt to save two worlds. Now there's a meeting place where the two realities co-exist, but Peter never was.

His absence rewrote bits of the timeline, like Olivia and the team having not yet met Lincoln Lee. More specifically, though, it's left Walter even more agitated and untethered, while Astrid seems a little harsher toward him than we remember. But where's Peter?

The Observer -- the one we've been seeing since the beginning -- noted that he's not as fully erased as he should have been, but as some part of him caused him to interfere in the natural order of things once before, he again could not complete the task of finally erasing Peter from existence.