Get a sneak peek at "Subject 13" now. We go back into the interesting past of Walter on this episode.
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Fringe takes us back to Walter's past on "Subject 13." Check out the official promo now.
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Fringe Season 3 Episode 15 Quotes

Walter: The texture of the universe has changed from my crossing. It cannot withstand any more damage.
Elizabeth: Neither can he, Walter. He is in constant distress.

Getting him back wasn't as easy as I thought.

Walter