Walter must rescue his son on the closing episodes of season two. The May 13, 2010 installment is titled "Over There."
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Walter must go to the alternate universe on "Over There." It's the first part of the Fringe season two finale.
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Broyles confers with Olivia in this scene from the two-hour season finale of Fringe. Part one is titled "Over There."
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Walter and company head "over there" on the season finale of Fringe. It's a two-part episode, the first half of which is aptly titled "Over There."
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Fringe Season 2 Episode 21 Quotes

I'll think I'll go and have a bit of a cry.

Walter

Today is the day for which you were created.

Walter