Season 4, Episode 15:
Ellen takes a drink from the poisoned cup given to her by her husband, and passes away while he holds her. She sees a datastream, then wakes up in a birthing chamber onboard a Basestar. She screams, but soon calms herself and takes in her situation. A copy of Cavil (named John) appears and greets her.
She remembers her life before the fleet and tells him that she named the Cavil line after her own father, indicating that she was one of the architects of the humanoid Cylons. They discuss her death on New Caprica and Saul's actions before he leaves.
Twelve months ago
John and Ellen are talking about the latter's experiences in the fleet. She asks if he still has nightmares, and he says that he removed his sleep subroutine twenty years earlier so that he would never need to dream.
He accuses Ellen and the other humanoid Cylons of being poisoned by human aspects. When she asks why he's pursuing human traits like murder and destruction, he counters that he wants justice for his ancestors, who were slaves to humanity.
Boomer enters and the trio speak briefly. John asks Boomer to tell Ellen how flawed the humanoid Cylons are before leaving, but Ellen counters that Boomer shouldn't let Cavil's quest for vengeance sway her own opinions.
After the destruction of the algae planet, John relates the story of D'anna's treachery to Ellen. They discuss the Temple's significance and the actions of the fleet, as well as the humanity of the eight mainline Cylon models. Cavil argues that he wants to be more like a machine and not a hybrid who has human aspects.
When he leaves, Boomer approaches Ellen and asks her if she regrets what she's done with the humanoid Cylons. Ellen says she has given the Cylons free will, but Boomer questions whether they could truly love anyone.
Cavil enters Ellen's room and tells her that the Resurrection Hub has been destroyed. He explains that the Cylons are in great danger and asks her to help rebuild the resurrection mechanisms. She says that she only knows part of the process, and that she would need the other members of the Final Five to understand the complete system. Cavil thinks she's lying, and threatens to cut her open to find out what he needs himself
In the present day, the fleet is still repairing itself after the attempted mutiny. Anders is prepped for surgery to relieve the pressure on his brain from the bullet wound, and Bill reinstates Tyrol as deck chief in the wake of Laird's death.
Tyrol tells Bill of the structural damage he saw while disabling the FTL drive, and Bill asks him to help repair the ship by whatever means necessary.
Anders (in a neckbrace) relates the history of the Final Five before Earth fell to Tyrol, Tigh and Anders. He says that Tyrol and Tory were in a relationship, and that all of them knew that the planet would be destroyed. He then explains that the Final Five reinvented resurrection technology with Ellen's help before Cottle orders everyone out of sickbay.
Bill and Roslin discuss the Quorum's death, and wonder if they should even bother rebuilding it. He offers to pick new members, and they both pledge not to tie it to the old Colonial ways. She also suggests that Lee should be her successor to the presidency.
The Final Four return to the sickbay and hear more of their shared history from Anders, who tells them that the Five left Earth and journeyed to the Twelve Colonies over the course of 2,000 years. He says that the Final Five made a deal with the Centurions to stop their war against the Colonies in exchange for helping them develop other humanoid Cylons, which led to the creation of the One-Eight models. Kara (who has also been listening) asks how there can be eight humanoid Cylons and realizes that one is missing, but Anders has a seizure before he can answer.
Although Anders objects to having the surgery (fearing that he won't be able to give the group more clarification), Kara authorizes it for him and says that the pressure needs to be relieved on his brain or he'll die. He continues with his explanations, talking about Cavil being the first model created and how he didn't believe in God or mercy.
He then says that Cavil betrayed the Five and boxed them, but later reawoke them with false memories. He also says that of the "missing model", Daniel/Number Seven, before he goes back into unconsciousness. Cottle and the surgeons take him into surgery.
On Cavil's Basestar, Ellen is also prepped for surgery to extract the information needed for resurrection. She asks why he's doing this as Boomer listens out of sight, and realizes that he's been enacting a centuries-long act of revenge against the Five for giving him human qualities.
Boomer takes Ellen out of her room towards the surgery bay, but then surprises her by heading to a confiscated Raptor. They flee the Basestar as it shoots at them, then the Raptor jumps away to find Galactica and the fleet
On Galactica, Bill authorizes Tyrol to use a Cylon technology to repair the rotting superstructure, while Anders is wheeled out of surgery but has no brain activity
- Being Human Sucks: Cavil gives an epic rant to Ellen explaining why he hates being human:Cavil: I don't want to be human! I want to see gamma rays! I want to hear X-rays, and I want to smell dark matter! Do you see the absurdity of what I am? I can't even express these things properly because I have toI have to conceptualize complex ideas in this stupid, limiting spoken language! But I know I want to reach out with something other than these prehensile paws, and feel the solar wind of a supernova flowing over me! I'm a machine, and I could know much more, I could experience so much more, but I'm trapped in this absurd body! And why? Because my five creators thought that God wanted it that way!
- The Bus Came Back: Ellen.
- Continuity Nod:
- Anders refers to the Cylons doing experiments which resulted in the creation of the first Hybrid while speaking to the Final Four in sickbay.
- When Tyrol and Bill discuss Galactica's deteriorating superstructure, the former points out that the ship has been through several stressful situations, including "jumping into an atmosphere".
- Cycle of Revenge: John Cavil enacted a centuries-long revenge plot against the Final Five for creating him, via boxing them, reactivating them with implanted memories, being the one to authorize the destruction of the Colonies and giving them front-row seats to the aftermath. Not to mention he had sex with the mind-wiped Ellen, despite knowing she created him.
- Dirty Old Man: Cavil has carried on a relationship with Boomer (who is technically his sister), and Ellen discovers that he's only done so to manipulate her into supporting his faction during the Cylon civil war.
- Disproportionate Retribution: John Cavil was clearly angry at the Final Five for designing him in the form of a human so he took it out on them by giving them a front-row seat to the fall of the Colonies. It is also implied that he instigated the second Cylon War because of his hatred of them.
- Foreshadowing: Anders mentions that the Cylons have a station called The Colony, which is where the Final Five originally developed resurrection technology.
- Gilligan Cut: From Boomer asking who she would want to love to a shot of Tyrol.
- HeelFace Turn: Boomer decides to escape Cavil's Basestar with Ellen instead of leading her to surgery.
- Identical Grandson: Cavil. Justified as Ellen, who considers him to be her son, based Cavil on her own father.
- Info Dump: Explaining the origins of the Cylons and Cavil's master plan, in an attempt to resolve most of the Kudzu Plot.
- Machine Empathy: Part of the episode deals with whether or not Bill should authorize Cylon technology to repair Galactica's rotting superstructure. He initially refuses on the grounds that "she won't know what she is anymore", but eventually tells Tyrol to do whatever he needs to "save our girl".
- The Man Behind the Man: The Cavils, particularly the one called John.
- Manipulative Bastard: Cavil, who had sex with a mind-wiped Ellen and is implied to have seduced Boomer to aid him during the Cylon civil war.
- Not Quite Dead: Ellen.
- Oedipus Complex: Ellen created John Cavil in the image of her father and then (mind-wiped of her past) had sex with him/one of them. Even worse, Ellen keeps referring to the humanoid Cylons as the Final Five's "children", because the Five helped the Centurions create the humanoid models. She also states that she made Cavil her "son" in the guise of her late father.
- Rousseau Was Right: A huge part of Cavil's Xanatos Speed Chess plan was trying to disprove this to the Final Five, by pushing humanity to its breaking point in the hopes of, in his view, showing how horrible humanity is to the Final Five, so that they would come back to him on their knees, begging for his forgiveness/love. Ellen straight up tells him he's wrong after she resurrects and regains her full Cylon memories and that even after everything that's happened she loves humanity just as much as she loves her Cylon children. Cavil is livid.
- Snap Back: Discussed. Galactica has undergone significant structural damage over the last two years, and the only way to repair it is with Cylon technology. Tyrol even tells Bill that the ship is old and had a lot of shortcuts taken for repairs prior to the fall of the Colonies.
- Special Edition Title: Summarizing the origin of the Cylons and flashbacks to the First Cylon War.
- Villainous Breakdown: Cavil gets one after Ellen says that the Final Five designed him to be as human as possible.
- Wham Episode: With the origins of the Cylons/Final Five fully explained and John Cavil's master plan revealed.