It is May 20, 2026. A badly injured Peter, now age 45, gets treated at Fringe Medical in New York City and is almost instantly healed. Astrid is there, as is the newly minted Agent Ella Dunham, Olivia's grown-up niece. Olivia is the boss now.
Peter is reunited with Olivia.
Peter wakes up in 2026. What's left of his world struggles to contain increasing Fringe events, including a wormhole through time and a terrorist group that wants to end the world.
When Peter destroyed the Other Side, he sealed their side's fate, because both universes are inextricably linked. Olivia, now his wife, is the boss of Fringe. Broyles is a senator, who springs Walter from prison so that he can help. But Walternate got trapped on This Side when he crossed over to ask for assistance.
Walternate wants Peter to suffer.
Back in 2011, Peter's back in the machine and it's only been 60 seconds.
Olivia climbs up to Peter, who greets her happily.
The Other Side's lab pops into the room, complete with Walternate, Brandon, and Bolivia. The machine releases Peter, who says that he now understands what the machine does and where it came from. The First People, says Walter. Yes, says Peter, but the First People are us. Walter, most specifically.
Peter tells the two Walters that Doomsday is worse than anything they could imagine - and that their worlds are inextricably linked. He's torn holes in both universes, which lead to this room. "A bridge," he says, "so that we can begin to work together, to fix -" And Peter simply disappears. No one even reacts. Instead, Walternate and Walter accuse each other of being horrible. Olivia says that maybe it's time we start to fix things.