With Fringe counting down the show's last episodes, each one offers something unique and special. As the team continues the fight against the Observers, Olivia offers a hope some had thought long gone.
As this week's episode begins, the team is still working to unify Walter's scrambled thoughts to retrieve his plan to banish the Observers. However, when the thought unifying device fails to work, Olivia reminds Walter he always documented his work. She suspects he's written the information down somewhere.
Walter says if he did, it's likely in his lab at Harvard. Etta tells him it's impossible to get into it because the Observers have marked it off-limits. That's when Walter says they can get in without anyone finding out, through steam tunnels running beneath the lab.
He's right. The team sneaks into the lab only to find that Walter ambered part of it. Inside the amber is his video camera. Walter says that's probably where the information's stored. So he sets to work building a laser to burn through the amber.
As they work, a loyalist security guard discovers them. However, Etta captures him. Then she begins torturing him to learn how to reactivate the lab's power.
The device Etta uses scrambles the man's atoms, aging him a few years. She tells her mother she intends to keep using it until he talks or his heart gives out.
Olivia's heartbroken to see what the Observers have done to her sweet girl. She tells Etta there's a better way to get what they need, but her words seem to have no impact on Etta.
The loyalist does listen though and he sees something in Liv he hasn't seen in a long time. It's a genuine determination to win back humanity's world.
As Walter and Astrid work on the laser, Etta and Peter disguise themselves as loyalists to get into the science building to get access to the power breakers. The loyalist agrees to give them his pass code, but says there's something else they will need.
He tells Olivia he'll give it to her if she promises to tell his son what happened to him. She agrees.
That's when the loyalist tells her, entry requires a retinal scan. He assumes the team will kill him to take his eye. That isn't what happens. Instead, Walter recreates his retinal pattern on the eyeball of a pig.
With the pass code and the eyeball, Etta and Peter successfully gain entry, but an alarm sounds in the security office. They contact the captive loyalist to see what he's doing in a restricted area. He tells them what Olivia instructs him to say. The deception works.
While walking through the labs, Etta sees a member of her resistance team inside the lab. When she moves in to take a look, she finds that it's just his head. The Observers are using it for experimentation.
Peter and Olivia's daughter goes ballistic, pulling her gun to kill the scientists. Luckily, Peter stops her. He promises her the Observers will pay for what they've done.
Once Etta calms down, she and Peter are able to turn the lab's power back on. It's just in time for Walter and Astrid, who've finished the laser. They begin cutting through the amber to retrieve the camera.
Once they're back in the lab, Etta tells her mother she intends to turn the loyalist over to the resistance. Olivia tries to discourage her, but Etta doesn't seem swayed. With Walter's help, she sedates the prisoner and heads toward the resistance camp.
She eventually stops and agrees to set the man free. He tells her he now intends to fight for the resistance. At first she doesn't believe him. Then he tells her something in Olivia's eyes made him belief that humanity could win. When he asks Etta why she let him go, she tells him it was something she saw in her mother's eyes as well. It was pity for all of them.
Back in the lab, the Fringe team successfully retrieves Walter's tape. It tells them they must track down other tapes to gain all the pieces of Walter's plan. Their work has just begun.