Rachel gets an eye exam from Ira, a Castor clone who was raised on his own by Professor Duncan (Rachel's mother). Charlotte, the clone girl, hangs around in the room. Rachel questions Ira about their whereabouts, where her mother is (after six weeks with no visit), and why he missed their last three appointments. He refuses to answer any questions and brushes off her insults. He gives her false eye a pigment treatment to help it look normal again.

In the comic book store, Hell-Wizard tries to entertain Kira by playing board games but she's unamused. In the basement, Scott and Cosima examine Sarah, trying to figure out what the implant is. They're unable to figure it out without examining the device on its own (which they can't do while it's in Sarah's cheek).

Rachel works on her physical therapy with Ira while Charlotte works on her schooling (geology). Professor Duncan shows up, happy to see Rachel progressing, but Rachel tells her off.

Sarah shows Mrs. S the video of the Colombian guy with the Neolution device in his cheek. S tells Sarah that she and Benjamin are looking into doctors who can remove the device. Sarah leaves to go tell Felix what is going on. S tells Sarah that they need to support Felix in trying to find his birth family.

Upstairs, Kira is distracted and blank-faced. She knocks the boardgame off the table, annoying Hell-Wizard.

Talking to Cosima, Donnie examines Alison's cheek to see if she has the implant as well. Donnie doesn't feel anything in Alison's mouth, so presumably she doesn't have one. Alison asks Cosima what the maggot is and Cosima explains that they don't know but they are in Neolutionists. Alison asks whether it would be useful if they could have one to study. She convinces a reluctant Donnie that they must exhume the body of Dr. Leekie from their garage floor.

Sarah goes to Felix's apartment and finds a strange young woman from the American South there alone. The girl mistakes Sarah for the drug dealer that Felix called. Felix returns to the apartment and identifies the girl as Adele, his paternal biological sister. Sarah brings Felix outside to speak to him privately and tries to convince him to ditch Adele to come help her with her problem. She suggests Adele might be a Neolutionist plant. Felix refuses to go and Sarah gets upset, telling him to piss off.

Donnie asks Helena to watch the kids for a few hours while he and Alison work on a "project" in the garage. Helena mentions that Sarah isn't returning her calls. She offers to help but Donnie turns her down, saying sometimes her type of help isn't what's needed.

Sarah goes on her own to track down Dizzy and finds him in a dilapidated warehouse type of building. She introduces herself as MK's sister, who was trying to find MK when she tricked him. She has him feel her cheek, convincing him to help her. Dizzy voices his theory about what the implant is -- he thinks it is in the jaw for proximity to the brain. Sarah asks about contacting MK but Dizzy tells her that no one finds MK -- MK finds them. Sarah asks him who the guy in the video was. Dizzy tells her word around town is that he was named Alonso Martinez.

Rachel eats dinner with Professor Duncan and Ira. Rachel correctly guesses that Duncan failed to recover the Castor and Leda original. Professor Duncan reveals that Charlotte was cloned from Rachel after four hundred attempts. Rachel becomes upset and kicks Ira and Professor Duncan out of the room, asking Duncan to allow her to die in peace, since she has failed to cure the clones.

Alison and Donnie dig in their garage and find the body.

Art watches the surveillance videos from Beth's apartment and sees Beth being visited by Zuko at home. Sarah arrives and shows Art the video of Alonso Martinez. She tells him she needs to get it out of her. She gives Art Alonso's name and he agrees to go to the department and look into him, seeing if he can find help. He tells Sarah to stay behind and rest.

Felix and Adele drink and chat about their shared father, an American who had an affair in England (with Felix's mother, who died when he was very young). Adele explains that her mother knew about the affair but not about Felix, whose existence was revealed on their father's death bed. Adele asks how his adoptive family feels about his looking for his family. Felix says he doesn't care.

Helena finally gets a call through to Sarah and tells her about the twins. Sarah congratulates her. Helena confides that she doesn't want them to grow up like she did. Suddenly, there's a knock at the door. Helena hangs up with Sarah and answers the door to find two detectives, who come in to question her about a triple homicide (the Portuguese drug dealers that Helena killed).

Donnie emerges from the garage and stumbles upon the questioning. He tells them he'll get himself cleaned up and runs to tell Alison. Alison stops digging and tells Donnie to get back out there with Helena. Donnie runs out.

Mrs. S tells Cosima that Benjamin may have found a doctor to help Sarah and rushes out, leaving Kira with Cosima. Kira zones out and when Cosima snaps her out of it, Kira confides that she had a dream -- in it, the other clones were setting Sarah on fire because she was "changing." Cosima is unnerved.

The police officers tells Donnie and "Alison" (really Helena) that Alison's campaign materials were found at the scene. Donnie answers questions for Helena about Alison's campaign, angering the detectives. Helena is miraculously able to identify everyone who worked on the campaign, shocking Alison and Donnie. Alison credits that ability to Helena being a trained assassin. Alison and Donnie get back to unearthing Leekie's body from the garage floor. The body is badly decomposed and disgusting, but they spot a polyp around where the implant is.

Rachel and Charlotte paint a picture while watched by a camera. Rachel silently paints a note seen only my Charlotte, asking if she got Rachel's message out. Charlotte paints back, answering yes. They paint over their notes and continue chatting. Charlotte coughs up blood, alarming Rachel, though Charlotte herself is unbothered.

Sarah watches the video of Beth holding the gun on Paul. She gets a call from Art, who reports that Alonso had a local address and that the previous year he flew in for one day and went to a dental clinic specializing in implants. Sarah goes to check it out. At the station, Art confronts Zuko about having paid Beth a visit at home after her suspension.

Alison and Donnie video conference with Cosima, telling her that he accidentally killed Dr. Leekie and that they now have an implant that she can use. Cosima is shocked. Alison cuts off Cosima's questions, telling her that they need someone with science knowledge to come retrieve the implant from the body because it is incased in a polyp.

Sarah arrives at the dental clinic, where she's intercepted by a young woman who mistakes her for Beth. Sarah goes along with it, pretending to be Beth. The young woman tells "Beth" that they know that she's digging and warns her against being back there. The woman tells her that she covered for her and that she herself signed an NDA and watched the surgeries herself. Sarah brings up Alonso Martinez, unnerving the woman, and tells her that she herself has an implant. The woman realizes that "Beth" is here to get it removed and reluctantly agrees to help.

S waits for Benjamin to show up. Ferdinand shows up instead. He questions her about why she's seeking a doctor with such an expertise, to take out nanotech. He wonders who in her group has the implant. S refuses any information. Art calls S, telling her that he thinks Sarah is in trouble -- she isn't with Felix and went on her own to investigate the clinic.

The young dental clinic worker remains behind with Sarah after the clinic closes. She ignores Sarah's question about why the device is for and begins the procedure to remove it. The clinic worker nervously tells Sarah that any slight movement will cause the toxin to erupt and kill her. The worker reveals that she's called her superiors to come deal with Sarah and that when "Beth" initially showed up she was instructed to misdirect her. 

Suddenly, Ferdinand shows up, killing the dental clinic worker and releasing Sarah. He reports to her that he received word from Rachel that Susan Duncan is alive.

Susan Duncan stands over Rachel as she's in bed and apologizes for her habit of detachment. Rachel is bitter because Susan raised Ira, a Castor clone, instead of her. Susan tells Rachel that she is the experiment and may take over one day, but she needs to be patient. She tells Rachel that everything is part of their quest for the greater good: to control human evolution and create a more perfect human being.