More outbreaks of Russian flu occur throughout England.
Jessica returns to the manor to meet the others, minus the captured Grant, and gives them the manuscript. She assures them that it's all there and the others demand to know where she's been. Jessica abruptly apologizes for using Ian as bait and asks where Grant is. She explains that the last page has the real name of Mr. Rabbit on it, and she gave a bunch of the pages to Grant. They tell Jessica what happened and she tears apart the manor looking for the hidden pages, while Alice wonders what they're going to do for Grant.
As Jessica searches, Becky asks if Wilson is okay after he was (apparently) stabbed by Letts. He says that he's fine and points out where the manuscript says that Carvel hid Janus in "his greatest achievement." Meanwhile, Becky tries to stop Jessica, saying that killing Mr. Rabbit won't change who her father was. Alice finally gives Jessica the pages that she saw Grant hide earlier.
The Assistant comes to see Grant in a police interrogation room and shows him that he has a taser. He asks about the drawings that Grant made, copying the manuscript, and explains that the numbers describe the molecular structure of the Janus protein. The Assistant congratulates him on his skill but notes that there are three five-digit numbers missing. Grant claims that he doesn't remember them and spits on the Assistant. Undeterred, the Assistant figures that the memory is buried somewhere and turns on a laptop. There's footage of Grant's mother at the grocery store and the Assistant calls his killer holding the camera and tells him to wave. He then leaves Grant a crayon and tells him to write in the missing numbers and buzz him when he has each one.
Ian and Becky read the manuscript and discover that Mr. Rabbit's real name is Letan. None of them recognize the name and Jessica asks Wilson to hack into central records at CCHQ. He agrees and she takes him out to get Internet reception. Outside, Wilson is surprised to discover that Jessica has brought back a state-of-the-art surveillance and communications van.
Once Anya is released, Michael and Jen take her to her new apartment and bring in a private doctor for a checkup. Jen tells Michael to stay out of it but hesitantly gives him a kiss. Once she leaves with Anya, Michael turns on the news and hears a report about how Geoff is being hailed as a hero for stepping up production of the flu vaccine and averting a crisis. Geoff gives a press statement telling everyone not to panic and promising that the flu vaccine will go out the next morning.
Later, Geoff calls Michael to his office and tells him that per the law, the flu vaccine must be independently tested in situ 24 hours before its release. Michael is the one required to run the testing, and Geoff tells him to sign off on it without asking questions. Geoff's team drives Michael to the lab, walking through a warehouse holding 64,000,000 shots of the vaccine.
At noon, Becky goes to the lake and finds Donaldson waiting for her. He tells her to stay back and shows her all of the Thoraxin he has. Becky tells him that she isn't giving him the pages and Donaldson complains, saying that he's already arranged a meeting to sell The Network the papers. He wonders why Becky came there and she asks him to one decent thing by giving her the drugs. Donaldson throws the drugs into the lake and Becky walks back to the manor.
When she gets to the manor, Becky looks for any signs of tremors in her hands. Ian comes in and she says that she doesn't know if Deel's has kicked in or not. He promises not to leave her and Becky describes the symptoms that will lead to her inevitable death. She tells Ian that she doesn't want someone watching her go through all that and goes over to Alice, who is sitting on the floor laying out the pages from the manuscript. Meanwhile, Ian walks over to Jessica's gun resting on the dresser, picks it up, and walks out.
In the van, Wilson does a search for Letan. He warns Jessica that it will take a while to go through the 56,000 databases and suggests she take the mobile unit out and scan the civilian channels. Suspecting something, Jessica says that she'll do it in the van and goes to work.
Grant tries to remember the numbers and watches his mother on the laptop video feed. He finally writes down a number and hits the buzzer. The Assistant comes in and transmits the first number, and tells Grant that he's correct. When he asks for the next two numbers, Grant says that he can't remember. The Assistant says that if he can't then he'll have no choice but to torture Grant's mother. Once he leaves, Grant opens up the laptop, removes a panel, and starts bending it into shape.
Michael is in the lobby of Anya's apartment when Ian barges in and puts a gun to his hand. He demands to know where Grant is and Michael insists that he is just protecting his family and that he can lead Ian to the vaccine. They go up to Anya's apartment and Michael explains to Ian that she's pregnant and The Network has been blackmailing him. He gives Ian the warehouse address and Ian checks the address on GoogleMap to make sure Michael is telling the truth.
When Ian leaves over to check the address, Anya hits him and grabs the gun, and then pistol-whips Michael when he tries to stop her. She then dials a number and, speaking perfect English, tells her superiors that they have a situation. They give her two minutes and Michael realizes that she's been playing him all along. He wonders if she's actually pregnant and Anya threatens to shoot him if he doesn't shut up. Furious, Michael yanks the carpet out from under her and hits her in the head with a soup can. Anya falls and hits a table, cracking her skull, and Michael grabs the gun. They realize that she's dead and Ian gently removes the gun from Michael's hand, saying they need to go.
Wilson continues his database search and waits until Jessica is busy scanning the channels. He opens a separate window and types an email to the Assistant saying that they have the manuscript. As Wilson prepares to send it, the search comes up with one hit. He quickly deletes the email and tells Jessica that he's got it. The name appears on a heavily redacted file from 1976 created by the Department of Defense in relation to the Committee of Genetic Discovery. In the footnotes there is a comment attributed to Letan. Wilson figures they changed Letan's name on the official documentation but overlooked the footnote. The committee members are all listed and Jessica figures that once they pull up their photos, they can identify Mr. Rabbit.
Inside the manor, Wilson downloads the information on the eighteen committee members. Fourteen were men, six are dead, and one is in a nursing home. Becky doesn't recognize any of the seven remaining men and Jessica says that they should kill all seven, dismissing it as collateral damage. Shocked, Becky says that she read in the manuscript what Carvel and Mr. Rabbit did to her. Jessica starts to snap at her, but Alice is shocked when Ian brings Michael in. Michael tells them that he knows where the vaccine is. He then sees the photos and asks why they have one of the Assistant.
Grant fills in the second number and buzzes for the Assistant. The man confirms the number is valid and tells Grant that he can go home once he provides the third number. Once the Assistant leaves, Grant looks at the sharpened piece of metal he was hiding behind his back.
Jessica tells Ian to hand over the gun, ready to go kill the Assistant. Michael insists that they need to stop the vaccine from going out but Jessica insists that it will stop when Mr. Rabbit dies. She ignores their objections and threatens to cut Ian's throat if he doesn't give her the gun. Ian figures that she's bluffing but before he can put it to the test, Alice calls them in and shows them how she's taken apart the manuscript and assembled the pages... revealing a molecular chain hidden among the art. The vaccine is a test, but if The Network gets Carvel's original work, they will have the pure tested Janus.
As the group prepares to move out, Michael congratulates Alice on her work. She tells him not to patronize her and Michael apologizes for calling the police on Grant. He explains about how he and Jen wanted a child, and Alice explains that her mother was infertile and that when they had the child, they considered her a miracle baby. Crying, Alice tells Michael that they shot her mother and he sits down and lets her talk about it to him. Becky and Jessica watch them together and then Becky says that she knows that Carvel experimented on her from reading the manuscript. Jessica says that in the published manuscript, the Devil experiments on her, but it's her father in the unpublished version. She figures that Carvel and Mr. Rabbit both deserve death, and assures Becky that killing Mr. Rabbit will make her feel better. Meanwhile, Michael finally hugs Alice, comforting her.
Out in the van, Wilson prepares to send an email about The Network to politicians, newspapers, and the police. As Ian watches, Wilson wonders if they're doing the right thing. He points out that they will eventually murder each other for food and water, possibly in their lifetime, and wonders if their enemy is right. Ian tells him to push the send button without a moment's hesitation. Wilson pushes the button sending the email and wonders if the authorities will take it seriously. Ian says that they will once they burn the warehouse to the ground.
Jessica is packing up the pages when Wilson comes in and tells her that he's downloaded blueprints of the Corvadt warehouse. He asks to go with her, reminding her that they killed his father and destroyed his life. Jessica grabs her gun and asks Wilson if he's ready.
That night, Ian, Becky, Alice, and Michael drive up in a van and parks outside the warehouse. Ian has Michael hide a shotgun beneath his coat and tells him to get to the video room and then have the technician disable all the relays. Michael goes up to the security desk and uses his security pass to get inside. However, as he brings the shotgun up, security guards tackle him. Outside at the van, more security men capture Becky, Ian, and Alice in the van.
Jessica and Wilson go to Corvadt's offices and break in. They're surprised to discover that there are no guards on duty. As Jessica tries to break into the office, Wilson grabs her gun and trains it on her. She realizes that he didn't send the email and Wilson tells her that he freed Letts. He insists that The Network is right and orders Jessica to give him the manuscript.
Grant hits the buzzer again and the Assistant comes in and checks the third number. He warns Grant that it's not right and the boy says that he got one of the earlier numbers wrong. When the Assistant bends over to look at it, Grant rams the makeshift blade into the man's throat. Dying, the Assistant tries to reach the buzzer but collapses before he can sound the alarm.
Wilson insists that they can't be the people that destroy humanity's chance at life. She refuses to give him the manuscript, draws her knife, and advances on Wilson. Wilson begs her to stop.
Grant uses the Assistant's transmitter to contact the man watching Grant's mother and tells him to stand down. The man shuts down the camera and Grant checks the Assistant's stomach and confirms that the Rabbit ideogram is carved on it.
Jessica says that the manuscript is the only thing left of her father and she's not handing him over. Grant comes out of the elevator behind Wilson, who turns. Jessica stabs Wilson in the side and then goes to Grant, who hugs her. She shows him the photo of Letan and Grant tells her that he killed him. Satisfied, Jessica takes Grant out, leaving Wilson to bleed out on the floor.
The guards tie and gag their four captives and take them to a lab inside the warehouse. Milner comes in and asks the guard if the four are all they found. She then draws a silenced pistol and has the guard ungag Michael. He asks her not to let Alice see them die and Milner agrees. The MI5 agent tells Alice to go into the closet, close her eyes, and count to 99. Once Alice leaves, Milner takes the gun, aims... and shoots the guard. She tells the trio that she's on her side and didn't want Alice to see her shoot the man, and then puts them to work. They dump gas on the crates and then toss in a Molotov cocktail and run.
Back at the manor, Jessica and Grant finally return to meet with the others. Jessica simply tells them that Wilson didn't make it. Grant and Alice doze off on the couch, and Ian and Becky lie next to each other. Becky finally says that they should give it a go and they kiss.
Later, Becky and Ian go outside and find Jessica waiting out front. Jessica points out that The Network must know that they burned the warehouse but despite that, the organization hasn't come for them. The couple tells Jessica that they're catching a train to the Highlands and staying for a month. They figure that will give Milner enough time to mop everything else up... if she has the manuscript. Jessica considers the manuscript in her hands and Becky says that they have to give it to Milner.
Grant watches as Michael prepares to take Alice with him while Grant goes with Becky and Ian. The boy doesn't think it's right given how Michael betrayed him, but Becky says that it's right for Grant to come with them until everything is sorted out. Grant angrily says that it's for the best and goes to the van. Alice comes over, says that she'll miss him, and gives Grant a hug and a kiss on the cheek. After a moment, he hugs her back.
Later, Jessica goes to meet Milner at MI5. Milner says that everything will be fine and takes her through the security checkpoints. Jessica is carrying the manuscript in a backpack and Milner tells her that, rather than take it public, she plans to destroy it.
Becky, Ian, and Grant go to the train station and Ian goes to get the tickets.
Milner escorts Jessica into her office and tells her to wait there while she gets a secure room. She tells Jessica that she can wait until Jessica is ready to show her the manuscript and leaves.
Becky collapses to the floor, convulsing, and Grant yells for help. Ian runs back and helps her up, and she asks Ian for water. Once he goes to get it, Grant holds a crying Becky and tells her that she's all right.
Jessica looks around Milner's office... and sees a rock like the ones that Carvel gave to her and Arby. She realizes that Milner is Rabbit and walks out of the office and down the hallway to the security checkpoint. The guards spot her and Jessica runs up the stairs
Becky tells Grant that their train is ready to leave and sends him to find Ian.
Jessica gets to the roof and bars the door as best she can. She takes out the manuscript pages and prepares to burn them.
Grant finds Ian, who realizes that Becky lied about the training leaving. They run back and discover that Becky is gone.
Jessica sets the manuscript pages on fire.
Becky runs to a train and boards it, while somewhere in the station, Ian tries to find her. Grant catches up to Ian and they realize that their friend is gone.
Milner and her men break down the door and Milner tells her men to go. Jessica wonders who Grant killed and Milner explains that the Assistant was so dedicated to the cause that he carved the ideogram into his own stomach. The MI5 agent admits that she helped burn the warehouse because the vaccine was irrelevant once she realized that Carvel's work was in the manuscript. Jessica defiantly tells Milner that she burned Janus, but Milner says that she only wanted the pages because she knew Jessica would bring them. The MI5 agent shoots Jessica in the leg to keep her from jumping, and then explains that Carvel thought that Jessica was his greatest achievement... and hid the most important thing in the world inside the person that he loved most. Satisfied, Milner tells Jessica that they have a lot to do.