At his former lab, Walter coaches Astrid on how to cut through the amber using a laser. They finally tunnel through to another videotape and play it. It turns out that the tapes aren't in order. The new tape is unclear in spots but the recorded Walter announces a set of coordinates in Pennsylvania. Walter doesn't remember the location and the maps show that there is nothing in the area. Walter finds some marijuana to sniff and says that he doesn't want to travel, but they refuse to let him stay behind.
Astrid stays behind to work on the tape while the others drive to Pennsylvania. They get out to check the area but find nothing. However, Olivia spots a small boy watching them from the woods and they go in after him. As they search the woods, Etta tells Olivia that as a child she used to imagine going on missions with her mother, but that Olivia is better than the one that Etta imagined. As they reach a clearing, armed men surround them. All of them have a barklike substance covering their faces, and they're all armed.
The men take the Fringe team to a camp with powered equipment and tents. After the men frisk them, the group's leader, Edwin Massey, comes out and addresses Walter by name. He wonders why they look the same as they did 21 years ago and Walter explains that they entombed themselves in amber to avoid capture. Edwin warns them that they've already been exposed and tells Walter that they've never met but he knows him very well.
Edwin takes Walter to a powered underground facility and explains that they have been recording and storing everything that happened since the Observers invaded earth. Among the data is everything on Fringe and Edwin tells them that his son River is a fan of theirs. Edwin's father started the database to make sure that the Observers didn't simply erase anything that disagreed with what they wanted people to believe. Walter asks about the bark skin and Edwin explains that it affects anyone that enters the area. However, the recordist camp couldn't move on because of the importance of their work and the fact that they couldn't move covertly because of the affliction. Edwin tells the team that they should leave but Walter explains that someone in the area is something they need to stop the Observer invasion. He admits that he can't remember what and Edwin begins searching the database for any relevant information.
Outside, Peter, Olivia, and Etta wait for Walter. River approaches them and shows them some comic books that he's made about the Fringe team's adventures fighting the Observers. He explains that he based his stories on them and wishes that he had been there with them to fight the invaders.
At the lab, Astrid cleans up the videotape and discovers that Walter had recorded a message about a mine. She calls Walter, who explains what is going on, and Edwin confirms that there is a gold mine in the area.
In Manhattan, Windmark receives a report from two loyalists that they picked up a scan of a van on the road.
Edwin takes the Fringe team into the mine and they find a vertical shaft with a rope going down. When they pull it up, they discover a petrified corpse tied to the end. He has the same bark growth on him as the camp members and Walter believes that something in the mine causes the reaction. The man died of it because he was much closer to the source than Edwin and the others. Walter tells everyone to leave until he can analyze the substance and determine what it is.
Alin, Etta's partner in the underground, receives a call from a double agent within the loyalist organization.
As Walter goes to work, the others settle down to wait. Etta gives everyone food tables and Peter asks Olivia about the name of a restaurant that they went to just after the invasion started. Much to his surprise, she doesn't remember. Walter informs them that the dead man's pore sealed over as a reaction similar to psoriasis to the high levels of carbon dioxide in the atmosphere, caused by the Observers altering the world to suit themselves. Edwin checks his records and discovers that a man named Donald went into the mines five weeks after the invasion started. He said that he was there to get samples of a red rock and was going to wait until a man from Boston arrived. Walter doesn't remember the man and Edwin explains that they recorded the man's stay because later he was taken away by two Observers. As they talk, Olivia notices a piece of the bark-like substance on Walter's hand and they realize that all of them are showing initial symptoms.
Walter is able to remove the early growth s but warns that he doesn't know how much longer they have until they can't be removed. He goes off to start testing substances that will resist the infection and make a suit out of i. Walter has Olivia and Peter go back to the van and remove the weather stripping so he can use it for his suit. As they leave, Etta receives a call from Anil warning her that the loyalists know where they are and are on their way.
As they work on the van, Peter notes that Olivia is upset and asks if it's because she can't remember the name of the restaurant. She tells him its name and explains that the reason that she's upset is because that she can't forget. They were at the restaurant discussing how Peter was going to a refugee camp in Maine. It was then that she realized that she couldn't go. Neither one of them would talk about their missing daughter and Olivia blamed herself because she had always believed she was destined for something greater than being a mother. That day at the restaurant was when she knew that she had to go back to New York because she didn't want to find Etta and face the realization that she was almost certainly dead. Etta made her feel ashamed when she mentioned earlier that she admired her mother, the mother that was willing to abandon her. Peter tells Olivia that they can't let anything ruin the second chance that they have together as a family. Olivia accepts what he says as Etta comes over and warns them that the loyalists are on the way.
The team warns Walter, who has determined that he needs copper to make the suit. A camp down the mountain has some of the copper, but Edwin insists that the team leave the area before the loyalists track them there and destroy the camp. River reminds his father that Edwin has talked on the radio to the other camp before, but Edwin warns that they don't know who the man he's been talking to really is. Peter offers to accompany Edwin to the camp and bargain for the copper, but Edwin refuses, insisting that the team is putting them at risk. Shocked at his father's attitude, River runs off.
Peter talks to Edwin privately and the recordist admits that he doesn't want to leave his son alone in the world by putting himself at risk. Peter figures that the rocks must be important and they need the suit to get them. Edwin tells him that he's not afraid to die but he doesn't know how to say goodbye to his son. He finally agrees to help and Peter asks him to call the camp. Edwin gets on the radio and the people at the other camp say that they don't have any copper. As the others leave, Edwin asks to talk to his contact, Ivan.
A loyalist force arrives on the road leading up into the mountain and identifies the van's tire tracks. Etta watches them and goes to warn the others.
River is drawing his comics when Edwin comes in to talk to him. He explains that a coward is someone who knows what needs to be done and doesn't do it, and says that he promised his wife that he would protect River as she lay dying. Edwin tells River that he plans to do his part and River admits that he doesn't want to lose him. When he says that he understands his father's decision, Edwin tells him that he will never understand until he has children.
Astrid continues working on the tape and finally cleans it up to get the details. She plays it for the others via the PDA and on the tape, Walter says that the rocks can be refined to provide a powerful energy source that they can use against the Observers. Edwin returns and tells them that the other camp has agreed to trade them the plans for a solar plant for two kilos of copper. However, he tells Peter and Olivia that he can't go with them and gives them a map to the rendezvous spot. As Peter and Olivia leave, Walter tells them to be careful.
When Peter and Olivia arrive at the rendezvous spot, they discover that no one is there. Peter quickly realize that Edwin never intended them to find the camp.
As Edwin approaches the mine entrance on h is own, one of his people on guard hails him.
As Peter and Olivia return to the camp, they hear a loud noise from the mine. Everyone goes to investigate and the guard explains that Edwin told him that the other camp had no copper. Rather than tell the truth, he lied and then went into the mine to get the rocks himself. The team goes inside and pulls up a bucket on a rope, and finds the red rocks inside. River looks down to the bottom of the shaft where his father lies dead, petrified. The guard tells the Fringe team that they need to leave now that they have the rocks.
River goes back to the camp and enters the data storage room. He discovers that Edwin left him a cube with photos of their family together. River then records a new entry detailing what his father did and how he sacrificed himself for a better future.
The loyalists pull over the van only to discover a local man driving it. The back is empty and the man insists that he found it abandoned.
Peter and the others hot-wire an old junker and drive away into the ruins.