“The Last Sam Weiss” is episode twenty-one of season three of Fringe.
Peter is unconscious in the hospital after being zapped by the machine in the previous episode, “6:02 AM EST”. Walter is checking on him when Astrid enters; the doctor plans to keep Peter sedated for another 12 hours, but his talks are stable. Hopefully, he won’t suffer any permanent damage. Walter isn’t sure, given the machine, and is fretting when Astrid reins him in. She suggests something to eat. Walter isn’t interested until she mentions tapioca pudding.
Holyoke, Massachusetts, and a teenage boy in the back of a car notices a glow in the sky, then the hairs on his arm stand up. He starts talking to his parents when the car in front of them is hit by a lightning bolt. The father backs up, then goes to take a look. On the road ahead, cars are being hit by bolts of lightning coming from nowhere.
Sam and Olivia are in the machine’s hanger; he says it isn’t supposed to be this way, as the machine is already on. Olivia says that Walter says the machines are quantum entangled and it was activated by the one on the other side. Sam asks how it could have been turned on, as it was built for Peter and only he can operate it. Olivia explains how Peter tried and was sent flying. Sam throws something at the machine, which it sends flying. He says the machine has been hotwired to think Peter is already inside and is repelling anyone and anything that tried to enter. The damage caused is because the machine is frustrated; it’s not a doomsday device even if it’s acting like one.
Sam says they need to disarm the forcefield and get Peter inside. He has the manuscript The First Ones books were based on, but with pages that were never published. There’s a box and a key to open it. Inside is a crowbar of sorts, to pry the forcefield open long enough to let Peter in. Sam doesn’t think Peter will die; the machine is indestructible and inside it, Peter should be safe.
Astrid and Walter are heading back from the cafeteria when they hear a doctor and a nurse talking about the lightning storms and the injuries caused. Broyles arrives; there are spontaneous dry lightning storms along the eastern seaboard. Walter wants to be with Peter for his last hours; Astrid convinces him to investigate, just as Olivia is doing.
Olivia and Sam are now at a cemetery at a sarcophagus. Sam explains that he’s not the first Sam Weiss. The first one was digging for mastodon bones when he discovered the manuscript. Other Sam Weisses wrote the books and searched for missing pages from the manuscript. They open the sarcophagus and there’s a box inside. Sam starts fretting, as the machine might destroy both universes and the other side weren’t supposed to turn it on first. He’s uncertain whether this is the right thing to do. Olivia says she’ll make it simple. She’s armed and he will take her to the key.
Walter is now flying a kite in a storm whilst Astrid uses some instruments. Walter is hit by lightning. Twice. When Astrid says this, Walter says that’s it; they need to go back to the lab.
Peter comes around in the hospital and starts heading out. Much of the hospital is deserted, because the staff are all coping with victims of the lightning strikes. Outside, there are more lightning strikes and fires. In Pittsfield, Peter gets in a cab and gives an address. The cabby checks on this, because the address is in New York City. Peter pays him.
Sam and Olivia are at a museum, where the key is. They speak to the museum’s head to work out the best way to the Native American room, where the key is hidden. And are told that there are lightning strikes inside the museum.
Walter wants to plot the frequency of lightning strikes, as well as seismic, thermal and radiation activity. When the maps are placed on top of each other, there are two hot spots. One where their machine is. One on Liberty Island. Walter heads to see Broyles; they need to take their machine to Liberty Island to reduce the damage. It’s not a permanent solution, and will make Liberty Island more dangerous. Meanwhile, Peter is heading to New York and may have lost some memory and Sam and Olivia are trying to get the crowbar. It’s rather unexpected when they find it.