Peter Bishop is changing, and not for the better. He’s been to Massive Dynamic and seen “the machine,” but the machine seems to have also affected him. This season’s 11th episode, aired on January 28, on Fox . The full episode of “Reciprocity” can be seen here on Hulu.com for a limited time without subscription.
The Fringe team meet up at Massive Dynamic and determine that Peter’s (Joshua Jackson) mere presence activates the machine. His father, genius scientist Walter (John Noble) is trying to regrow a part of his brain he’d had removed so he can think like his doppelganger in another universe, “Walternet”. Olivia Dunham (Anna Torv) is back from the alternate universe and coming to terms with the impact her double “Fauxlivia” has had on her life, and her relationship with Peter.
That night, Peter is sneaking about, lying about his whereabouts to Walter. They share sandwiches at home as Walter confesses he is doing all he can to try to figure out what’s going on with Peter and the machine. “I know that you want to help me, I don’t think that you can this time. You can’t protect me from everything.” He says, reminding Walter of a major theme of the show.
The next day, tests are run at Massive Dynamic on Peter by a gifted biomedical engineer, but they aren’t helping. Nothing medically points to a connection between Peter and the machine, despite the fact he suffered a nose bleed and the machine kicked “on”. Walter asks Nina (Blair Brown) to help him regrow his brain cells, which she grudgingly agrees to do.
A body is found on the grounds, and it turns out to be a shape shifter whose data storage disk has been removed. The victim’s name is found on Fauxlivia’s computer, and Agent Broyles (Lance Reddick) and Olivia come to the conclusion a mole must be undermining their efforts and feeding information to Walternet and killing off shape shifters before they can be found. Olivia offers to help search Fauxlivia’s files, but Broyles and Astrid (Jasika Nicole) discourage her, given that the files are somewhat like a diary. The diary reveals personal details about her relationship with Peter. Eventually, though, she argues that the future is more important than the past and begins to look through the material.
Research indicates that a retro-viral serum will help regrow Walter’s brain cells and before he they can determine the right one, he snorts a vial. It later proves to be from a chimp and, in a nod to Sir Arthur Conan Doyle’s “The Adventure of the Creeping Man”, he begins to exhibit chimp behavior. He admits he’s not sure if what he did was dangerous, but suggests his immune system will reject the chimp DNA.
Bodies continue to stack up, making Olivia wonder how the mole is staying ahead of them. A shape shifter is seen fleeing later and attempts to change shapes, but after the process is nearly complete, it is killed. Peter is revealed to be its killer. Walter figures out what’s going on, actually catching Peter in the midst of one of his hits. Peter tells him he’s trying to find out what they know.
“They’re soldier’s, Walter. They’re here to kill us. Besides, they’re not even human. I’m not doing anything wrong.”
While realizing how similar she is to Fauxlivia through her files, Olivia discovers a letter substitution code that shows which people are shape shifters. They rush to find the surviving pair from the list, but Peter has already killed them both. She arrives on the scene of the final killing, but finds nothing but the body.
Back at Walter’s home, Olivia tells Peter again how they are always a step behind. After she leaves, Walter says he knows what’s happened. The machine has weaponized Peter.
Back at Massive Dynamic, Nina’s head scientist informs her that three copies of the book of the first peoples have been located and that someone else had started looking for the book three years ago- Dr. William Bell.