Season 2, Episode 22:
Over There
Walter and Olivia discover that Peter has agreed to return with his real father, Walternate, to his original universe. September leaves Olivia a note suggesting that Peter is prophesized as the one responsible for the end of the world. To warn Peter, the team work with Massive Dynamic to come up with a way to cross over. They form a plan that takes advantage of Olivia's universe-hopping ability, and recruit three other Cortexiphan test subjects who have unique abilities: Nick Lane, Sally Clark, and James Heath. The team—composed of Walter, Olivia, Nick, Sally, and James—successfully arrives in the alternate universe. James dies shortly after arrival, but the rest manage to evad the alternate Fringe Division, who had detected their arrival. They discover that Walternate is the Secretary of Defense.
Peter reunites with his mother, Elizabeth, while Walter's team journeys to meet with William Bell at Central Park. Instead of Bell, the alternate Fringe Division appears, and attacks Walter's team. Nick is shot and Sally stays with him; she produces a suicidal fireball that burns both her and Nick to ashes and severely burns the alternate Fringe Division's principal investigator Lincoln Lee. Walter is shot and walks to the hospital. Olivia follows her alternate counterpart and encounters Bell, who insists he did not betray their location to the Fringe Division and tells her that Walter is in trouble. Walternate is seen in the room housing the doomsday device Peter will be a part of, and leaves with its final component.
Tropes:
- Allohistorical Allusion: The Alternate Universe has a lot of fun with this.
- Richard Nixon appears on the 50 cent piece instead of John F. Kennedy. The $20 note depicts Martin Luther King Jr., and is colloquially referred to as a 'Junior'. Lincoln's reaction to the note Fauxlivia finds from our universe would suggest that Andrew Jackson was never President in their universe.
- The Hotel Attraction
designed by Antoni Gaudi, which was never built in our universe, appears as part of the New York skyline with the name Grand Central Hotel.
- Different World, Different Movies: At one point Walter and Olivia's team wait at a bus stop advertising the eleventh season of The West Wing.
- Last Day to Live: When the Cortexiphan team is briefed on their mission, they ask for a day off to get ready. It's implied they know this trope is in effect, as they spend the time getting together or visiting loved ones — in Olivia's case, giving her cross necklace to Ella — as if for the last time.
- Suspiciously Similar Substitute: Sally Clark, a Cortexiphan kid with pyrokinesis, appears to be one for Nancy Lewis, a Cortexiphan kid with pyrokinesis, from "The Road Not Taken".
- Special Edition Title: The first time the red title sequence appears for an episode set in the Alternate Universe.
