Fringe: Season 2, Episode 22

2 - 22: Over There: Part 1

Walter and Olivia discover that Peter has agreed to go with his real father, "Walternate", back to his own dimension. An Observer leaves them a paper indicating Peter to be the major subject of a prophecy, which foretell him being the one responsible for the end of the world. In order to warn Peter of this role, the Fringe Division come up with a way to cross over, amplifying Olivia's dimension-hopping ability with three other Cortexiphan subjects: Nick, Sally, and James. They along with Walter and Olivia successfully head over to the Other Side, and manage to avoid capture by the alternate Fringe Division. Walter's team heads to meet William Bell at Central Park, but is split up when they believe that Bell has betrayed their location and the alternate Fringe Division attacks them. Nick and Sally are killed, but not before seriously burning the Fringe principal investigator, Lincoln Lee. Walter is shot and hospitalized. Olivia follows her alternate counterpart and encounters Bell, who insists he never betrayed them, and tells her that Walter is in trouble. Walternate is seen leaving with the final component of the device Peter will be a part of.