“The Day We Died” is episode twenty-two of season three of Fringe and the season finale.
In the previous episode, “The Last Sam Weiss”, when Peter went in the machine, he was next in the future, one where there’d just been some kind of incident. Peter is rushed to what turns out to be Fringe Medical, New York, on May 20th, 2026. He has a shrapnel wound and Astrid, wearing a Fringe Division patch, tells him he’s in good hands as his wound is cauterised.
A young woman arrives and asks how Peter Bishop is doing. She doesn’t have a badge as she was only promoted to Fringe last week. She has a barcode. That’s scanned and she’s greeted as Agent Dunham. Olivia comes to greet the now-adult Ella, who says what she remembers from what sounds like an attack. Was it the End of Dayers? Olivia confirms they think it was Moreau.
Peter and Astrid arrive. Peter says he’s fine; Astrid says the doctor told him to stay off his feet for a few days. Ella asks if Peter remembers what he was saying about being in the machine in the past. He doesn’t. But he remembers the present. The news announces a stage 3 tear and that Moreau is claiming responsibility.
Moreau and two other men are setting up devices in an opera house. They shoot a man who sees them, and leave. The device activates and destroys a chunk of the building. Afterwards, Peter, Olivia and Ella arrive at the scene. Astrid says that the terrorists entered through the side fire door; the alarm was disabled. And they think they’ve found an electrolyte. One of the devices used.
Fringe HQ in Boston and Astrid and Peter are working on the device. She’s handed witness statements and leaves as Olivia joins Peter. Peter can’t tell how the device works. It shouldn’t work. There’s probably only one person on Earth who can tell how the thing functions. Walter. Peter says Olivia should call in any markers she has.
Peter heads to see Walter in a prison with the device. Walter thinks it must be bad if they’re allowing Peter to see him. Peter tells Walter the rumour the Sun is burning out isn’t true, but the one about the massive increase in kappa radiation is. A wormhole in Central Park. They were finally able to amber it. Walter says it shouldn’t emit that radiation unless it’s through time. It is. About 250 million years into the past. Peter explains they need Walter’s help. The device is being used by terrorists at soft spots to trey and accelerate the end of days. If they can figure it out and trace the parts, they could stop them before it’s too late. Walter needs his things, as he can’t examine it in prison. But they both know that won’t happen.
Peter heads to see Senator Broyles. Who has an artificial eye. He wants a temporary furlough for Walter. Broyles can only offer to consult from prison. Because they’re applying Band-Aids to try and stop the world falling apart and Walter is held responsible. Peter says he knows Walter and his intentions weren’t this. Broyles says there’s not a single person who hasn’t lost someone. He can’t begrudge them their anger. Peter doesn’t. They may be applying Band-Aids, but it’s something. If they can figure out this device, Peter guarantees they can prevent future cases.
Walter is brought back to his lab. It’s empty; everything is in evidence. Olivia is on it. Astrid is a field agent, now, and she won’t be here. Olivia arrives with the equipment and Walter congratulates her on her wedding to Peter. This is the first opportunity he’s had to do so. One of the movers knocks something fragile over. But Olivia catches it with her mind before it hits the floor.
Moreau is meeting with someone. The next target is the wormhole in Central Park, and the device is more powerful. The man he’s meeting is Walternate. Who says it won’t be long before this world joins his own.
In the lab, Walter is struggling with the device. Even if he is successful, the world is still ending. Destiny was set the day the machine was triggered. They didn’t understand until too late that both worlds are inextricably linked. Without one, the other cannot exist. The day the other world was destroyed was the day they sealed their fate. For all intents and purposes, the day they died. Peter says they don’t know that for sure. Walter asks about Walternate. Peter says he’s become a recluse. Walternate came over to try and save his world, and was stuck when it was destroyed. And he has the same face of the most reviled man in the universe. Peter says he got in the machine and destroyed the other universe. Walter says it began with him.
Walternate is trying to destroy the world. To make others suffer, as he did. But all of this may be a glimpse of the future, so that the bad future won’t happen. There are threads leading into season four and “Neither Here nor There”.