Sarah reels from a shocking discovery, and becomes desperate to find answers; after following a lead, Sarah finds herself in a harrowing encounter.
This episode contains examples of:
- Big Brother Is Watching: Susan Duncan has cameras all over Rachel and Charlotte's living quarters, so the two of them use secret messages to share their real thoughts.
- Big Damn Heroes: Ferdinand, of all people, rescues Sarah from the neolutionists dentist.
- Body Horror:
- Sarah goes back to Dizzy, the man who showed her a video about the creatures in the previous episode. He speculates the reason they're implanted in the cheek is because they're meant to eventually burrow into the victim's brain.
- Donnie and Alison learn that Leekie had one of those creatures implanted in his own cheek.
- Calling the Old Man Out: Rachel is tired of her mother's games and lets her know it.
- Dead Person Impersonation: Sarah pretends to be Beth when she learns that a dentist connected to the death of Alonzo Martinez (the man she saw die in the video) was one of Beth's old contacts.
- Dissonant Serenity: The dentist Sarah trusts to get the creature out of her reveals that she works for the neolutionists and has been playing her the whole time, while holding onto a instrument such that the slightest movement could kill Sarah. Yet she maintains a calm expression and a warm, soothing tone of voice all the while. In fact she tells Sarah she ought to feel lucky to have been chosen.
- Eye Scream: Ira tinkering with Rachel's mechanical eye. Sure, she can't actually feel anything, but still it is rather unsettling to watch. Lampshaded by Charlotte, who says this is her least favorite part of their routine.
- Genki Girl: Adele, Felix's biological half-sister.
- The Greater Good: This is apparently Susan's motivation — taking control of human evolution for the sake of perfecting mankind.
- Homeschooled Kids: Charlotte, now living with Rachel permanently, studies via online courses. She seems particularly interested in geology.
- Internal Reveal:
- Donnie confesses to Cosima that he killed Leekie.
- Ferdinand reveals to Sarah that Susan Duncan is alive.
- Long-Lost Relative: This time it's Felix's turn. He finds his biological half-sister, Adele, and they talk about their families.
- Oracular Urchin: Kira tells Cosima that she had a vision of the other clones setting Sarah on fire because she was "changing". Cosima is visibly disturbed.
- Organic Technology: The creatures that the neolutionists are putting into people are partially mechanical and have some as-of-yet undetermined function.
- Parental Abandonment: Susan tells Rachel that she left because attachments were unacceptable, but that she's been observing her her whole life. Rachel is understandably resentful, especially since Susan chose to raise Ira instead.
- "The Reason You Suck" Speech: Rachel gives her mother one, saying that she knows she failed to find the original. Susan in turns calls Rachel ungrateful and a huge disappointment before storming out of the room.
- The Reveal:
- Leekie had a creature in his cheek too.
- There's another Castor clone named Ira. He was raised apart from the others by Susan Duncan.
- Charlotte was cloned from Rachel specifically. And she's been coming down with the clone disease.
- Susan has been watching over Rachel for years, and Rachel actually wasn't supposed to know about Helsinki.
- Slashed Throat: How Ferdinand kills the dentist who was about to hand Sarah over to the neolutionists.
- Squick: In-universe. Donnie and Alison learn the hard way that digging up a dead body is really, really disgusting.
- Twin Switch: Helena has to pretend to be Alison when a couple of police officers comes to question her about the Portuguese drug deals that Helena killed back in season 3.
