At Walter's former lab at Harvard, Walter and Astrid continue cutting into the amber and finally recover another video tape. Emerging, they play it and discover that Walter stored the tapes out of order. Walter on the tape gives them coordinates to a location in Pennsylvania. The real Walter doesn't remember anything about the location and according to the files, there's nothing in the area. He finds some hidden marijuana and sniffs it and then says that he should stay behind at the lab to regroup while the others indicate the location.
While Astrid stays at the lab, the others take Walter along with them anyway and drive into the middle of the area. There are no signs of any people or buildings and Peter wonders what Walter was doing out there 21 years ago. Olivia spots a kid watching them from the woods and they move cautiously after him. As they go in, Etta admits to her mother that she used to imagine going on missions with Olivia, and that Olivia is more than she imagined. Armed men surround them with guns.
The men take the Fringe team through the woods to a camp with powered equipment. Each man is covered with black bark-like lesions. After they're searched, a man steps out and addresses Walter by name. He wonders why they haven't aged and Walter explains that they were trapped in amber for 21 years. The man introduces himself as Edwin and tells them that they've already been exposed. When Walter asks if Edwin knows him, Edwin says not in the way that he thinks.
Edwin takes Walter to an underground chamber and explains that they store all of human history since the invasion began. Information on Fringe is stored there and Edwin explains that his son River is an expert on the subject. Edwin's father started the historical record because they needed to maintain the real history, fearing the Observers would rewrite it. When Walter asks about the black disease, Edwin explains that it affects anyone in the area, but they couldn't leave because their work is important. They can't transport the data without drawing attention because of their distorted appearance. Edwin says that no one has come in a long time and tells Walter that he and the others should leave. Walter informs him that there is a plan to destroy the Observers, but he can't remember it. He's sure that he's been there before and Edwin searches all of the data for any information on Walter.
Edwin's son River approaches Olivia and the others and shows them some comic books about Fringe Division's adventures against the Observers. River has made them based on stories he's heard about them and wishes he had been there so that he could fight the Observers.
At the lab, Astrid replays the tape and tries to clean up the audio. She discovers that Walter has told them to find a mine. She calls Walter, who says that there is no record that he was there, and tells him what she's learned. Edwin tells them that there is a gold mine in the area.
In Manhattan, two Loyalists inform Windmark that they spotted the Fringe team in Pennsylvania.
The Fringe team goes into the mine and proceeds to a vertical shaft leading down. They find a rope attached to something and pull it up, and discover a corpse tied to the other end. The man was trying to climb back up when he died, and he has the same bark-like growth as the others. Walter confirms that the tissues show signs of calcification and suggests that the mine is the source of the reaction. He tells the others that they have to leave until he can analyze the infection and determine what it is.
Alin receives a call from an inside man at the Observers' headquarters.
As they wait at the camp, Etta hands out food pills and Peter talks about how he and Olivia went to a restaurant just after the invasion. She doesn't remember, much to his surprise, Walter takes an air sample and confirms that the man died of asphyxiation when every pore in his body sealed up in an effort to protect the man. He theorizes that the high levels of carbon dioxide that the Observers are introducing into the air have caused an immune reaction similar to psoriasis. Edwin shows them an entry about how man came there five weeks after the invasion and went into the mines to gather some red rocks. The man's name was Donald and he said he was waiting for a scientist from Boston. Walter doesn't remember Donald and asks why they recorded the man's arrival. Edwin says that he was taken away by two Observers and Walter wonders why he would have wanted rocks. Olivia notices that Walter's hand shows signs of the bark-like infection and they realize that they are all showing symptoms.
Walter cuts some of the substance off of Olivia' neck and confirms that it hasn't rooted into the dermis yet. He doesn't know how long they have until it can't be removed. He then prepares to find a substance that is proof against the infection so that they can make a suit. Walter sends Olivia back to the van to get some weather stripping while Anil calls Etta and tells her that the Loyalists are tracking them.
As they go to the van to remove the stripping, Peter asks if she's upset that she can't remember about the restaurant. She tells him the name and says that what upsets her is that she can't forget it. Olivia describes how Peter was discussing about going to a refugee camp in Maine and she realized that she couldn't go. There was a wall of missing-person flyers on the wall of the restaurant and neither one of them would talk about how Etta was missing. Olivia explains that she felt responsible and that she believed she was destined for something else than motherhood ever since the cortexiphan trials. When they lost Etta, Olivia believed that she was being punished for not appreciating their daughter. That was the day that she knew she had to go back to New York because she didn't want to find Etta dead. When Etta told her earlier that she admired Olivia, Olivia couldn't take it since she was willing to run away. Peter tells her that the past is the past and to not let it get in the way of their second chance to be together. Etta comes over and tells them that the Observers are tracking them.
Olivia and the others tell Walter that they're running out of time, but he says that he needs copper to finish work on the suit. He knows about a camp down the mountain that has some of the metal, but Edwin tells them that the team needs to leave immediately before the Observers arrive. River mentions that Edwin has talked to the other camp on the radio but his father warns that they don't know who he is or where he is. Peter offers to go with Edwin and barter for the copper, but Edwin tells them to go back to Boston and finish the suit. When he insists that the Fringe team is putting them all at risk, his son runs off, shocked at his father's attitude. Edwin stares at his son, realizing what he thinks of him.
Later, Peter approaches Edwin, who admits that he doesn't want to leave his son alone in the world. He tells Peter that the men at the camp are bad people, but Peter insists that the rocks must be important. Edwin says that he's not afraid to die but he doesn't know how to say goodbye to his son, and then asks Peter what he needs him to do. Peter tells him to get on the radio and tell the other camp that they're coming.
Edwin contacts the other camp and says that he wants to barter for copper. They say that they don't have copper and Edwin asks to speak to Ivan.
A Loyalist forces arrives in the area and follows the tire treads up into the mountains. Etta spots them coming up toward the camp.
Edwin finds his son working on his comics and tries to explain that being frightened doesn't make one a coward. A coward is someone who knows what needs to be done and doesn't do it. Edwin tells River that he has a lot to lose and that he promised his dying wife that he would protect River no matter what. He's decided to do his part and River says that he doesn't want to lose him. River says that he understands but Edwin says that he won't until he has children of his own.
At the lab, Astrid continues cleaning up the tape and finds Walter describing how the rocks can function as a powerful energy source once they are properly refined. She transmits the video to the group at the camp, and they watch as the Walter on the tape says that they'll need 40 pounds of the crystal. Edwin tells them that the other camp has 2 kilos of copper and is willing to trade. However, he tells them that he can't go with them. Edwin tells them to look for Ivan and give them the schematics they have of a solar generator. Peter takes the plans and a map to the camp's location, and Peter assures him that they'll be back soon. As he and Olivia leave, Walter tells them to be careful.
Olivia and Peter drive to the location on the map but there's nothing there. Peter realizes that Edwin didn't want them to find the camp.
Edwin approaches the mine entrance and one of his people hails him.
At the camp, Etta and Walter hear a banging noise and realize that it came from the mine. As Peter and Olivia return, they run to the mine entrance and the man on guard explains that Edwin called the camp and discovered that they had no copper, so he went into the mine. Walter and the others run in and discover that Edwin has hoisted up buckets of the rock. River looks down the shaft, crying, and the guard tells the Fringe team that they have what they needed. At the bottom of the shaft, Edwin lies dead, his skin hardened over.
Back at the camp, River goes to the data bank and discovers that his father left him a cube. He plays it and finds photos of his mother, and then records what his father did and how he sacrificed himself for a better future.
The Loyalist patrol pulls over the van and discovers one of the camp members driving it. He claims that he found it on the side of the road.
Peter and the others steal a car and drive away in an old junker.