Peter (Fringe episode)

The introduction scene follows from "Jacksonville", where Olivia (Anna Torv) has discovered, through her Cortexiphan-induced abilities, that Peter (Joshua Jackson) is from the parallel universe, and Walter (John Noble) takes her aside to tell her how this came to pass, shown to the viewer in an extended flashback.

In 1985, Walter and William Bell had theorized the existence of a parallel universe, and created a window-like device to observe it. Though they use their observations for military benefits, Walter has a more personal interest in the parallel universe, to seek a cure for a genetic disease crippling his son Peter (Quinn Lord). "Walternate", Walter's doppelganger in the other universe, is also seeking a similar cure, his Peter suffering from the same disease.

The prime universe's Peter succumbs to his illness and dies, and Walter and his wife Elizabeth (Orla Brady) mourn their loss, supported by Walter and William's friend, Nina Sharp (Blair Brown) and Walter's lab assistant, Carla Warren (Jenni Blong). Walter, through his window, shows Elizabeth the other Peter, and asserts they should be happy knowing another Peter exists. Later, Walter watches Walternate explore other cures. Walternate is distracted by the arrival of an Observer, September (Michael Cerveris), and fails to see the telltale color change indicating a cure. Walter is able to recreate and stabilize Walternate's cure, and then decides to use untested equipment to cross over to give the cure to Peter. Carla tries to stop Walter, knowing the technology could damage the fabric of space-time, and contacts Nina for help. Separately, September informs his fellow Observers that he may have made a mistake and assures them he will correct it.

Walter sets up his equipment on the frozen ice of Reiden Lake, near a cabin where Elizabeth and Peter are staying; Walter theorizes the frozen waters will buffer the effects of the crossing. Carla arrives with Nina, and both try to talk him out of it. When Walter realizes William is not with them, he takes this as an implicit sign of William's consent to his plan, and activates the portal. Nina attempts to tackle Walter as he steps through, but instead part of her arm disappears in the portal as it closes; Carla rushes her to the hospital.

In the parallel universe, Walter finds the cure vial shattered when Nina tackled him and he devises a new plan: to bring Peter back, administer a new batch of the cure, and return him. Meeting the parallel universe's Elizabeth, he explains he is taking Peter back to the lab for some tests. As Walter walks Peter back across the lake to the portal, Peter realizes that Walter is not his real father. They cross through the portal safely, but the ice has weakened and both fall through, losing consciousness. Walter wakes to find September driving him and Peter back to Walter's lab. September warns that "the boy must live", and leaves Walter to drive the rest of the way. At the lab, as Peter receives the cure, Carla informs him that William will see to replacing Nina's arm. Elizabeth arrives unannounced, and is overjoyed to see Peter, even though it is not her child. At that point, Walter realizes he will never be able to make himself return Peter to his proper universe—the pain of losing their child for the second time would be too great.

In the show's conclusion in the present day, Walter tells Olivia that his crossing is what caused the crack between the two universes, including the Pattern on their side, and leading to the oncoming "storm" that William warned Olivia about.

The episode's teleplay was co-written by supervising producer Josh Singer and co-showrunners Jeff Pinkner and J. H. Wyman, based on a story by Singer, Wyman, Pinkner, and consulting producer Akiva Goldsman. House M.D. veteran David Straiton served as episode director.^[2]

Fringe began casting for an actress to play Walter's wife Elizabeth in November 2009. In their report, they were looking for a woman roughly forty years old who was described as being "strong (yet broken), intelligent, attractive, likable, lovely and extremely versatile".^[3] In December 2009, Entertainment Weekly announced Irish actress Orla Brady had been cast as Elizabeth Bishop, a possible recurring character.^[4] Some critics questioned the casting, as they considered Brady to be too young and were unsure if she would appear in the present or a flashback sequence.^[5]

"Peter" was set in 1985, with a much younger Walter and Peter Bishop, and also features an appearance by Walter's wife Elizabeth. Actor John Noble used material he had created since the airing of the pilot, which he explained was his sense of "what was this man like before he deteriorated."^[6] The production crew tried different methods with the actor to create a younger Walter, such as changes to his hair, make-up, and wardrobe;^[6] they ultimately decided on using "tabs" to keep the wrinkles in his face back. He did not wear a wig, but the crew did add parts to the front and back.^[2] When asked what preparation went into playing a younger Walter, Noble explained:

"Quite a lot, but in the sense in my preparation to find the Walter that we all know now, I had to go back to him right at the beginning to see where he came from. So that process was started before the pilot really, what was this man like before he deteriorated, so I was able to revisit that. Physically, of course, what I had to do was capture the energy, to capture the physicality of the man, the vocal physicality of the man, this was my task. I was aided enormously by my hair and makeup and special effects people here in terms of getting the overall, and indeed wardrobe helped a lot as well. And then we, the shot up through these beautiful lenses that we got a different feel to the episode than we would now. All of those elements work together... to create this version that you see in the episode."^[7][8]

The episode was shot through special lenses to make it more reminiscent of the decade.^[6] At Peter's funeral, actress Blair Brown wanted her character Nina Sharp to wear sunglasses, because she thought Nina would not share her emotions at the funeral. Unlike Noble, Brown wore a wig. The scenes at Reiden Lake were actually shot on a parking lot, and the crew placed a covering over it to simulate the cracks normally on a lake.^[2]

To reflect the episode's setting in 1985, the typical title credit sequence was redone using different music, the Amelia font for early computer type for the show's logo, and terms that were novel science at the time, such as "virtual reality", "genetic engineering", and "personal computing".^[6][9] Pinkner later recalled, "One of our writers said off-handedly that if we’re doing a show from 1985, shouldn’t we do a credit sequence from 1985, and literally, we pounced on it". He and Wyman asked J. J. Abrams, who wrote the original credit sequence melody, to write a 1980s version; Abrams was "very, very happy to do that," according to Wyman.^[10]

As with other Fringe episodes,^[11] Fox and Science Olympiad released a lesson plan for grade school children based upon the science depicted in "Peter"; the lesson's intention was for "students [to] learn about the challenges of effectively communicating scientific principles and concepts, especially via non-verbal methods."^[12]

In viewing the parallel universe through the window, Walter and others witness a zeppelin docking at the Empire State Building, which was originally part of the building's purpose until it was shown to be impractical.^[13] In a scene that takes place in the parallel universe, the Observers are seen leaving a theater having watched Back to the Future starring Eric Stoltz; in reality, Eric Stoltz was originally cast in the role of Marty after Michael J. Fox was unavailable, but after filming for several weeks, Stoltz was replaced by Fox.^[9][14]