In this episode, Derek Reese dies, shot in the head by a Terminator posing as the Water Delivery Guy.

Sarah fulfills the promise she made to Derek in eiposde 1x07, The Demon Hand, to show him where his brother Kyle is buried.

visual: Sarah and Derek stand in a cemetery, looking at all the unmarked graves from 1984.
Sarah: I don't know which one is his. (meaning Kyle Reese)
Derek: Doesn't matter. Grass, trees...could be worse.
Sarah: Could. It's been twenty five years.
Derek: Desert. You sent me to some desert.
Sarah: I did.
Derek: Funny thing about the desert. You don't find many lighthouses there.
Sarah: We stopped to see Charley.
Derek: So you did.
Sarah: Charley's dead.
Derek: So I heard.
Sarah: From who?
Derek: John.
Sarah: He called you, too.
Derek: Good thing. Might not have found you. My brother buried out there, I thought...that counted for something between us.
Sarah: Well, John counts for more. And you keep too many secrets for my tastes. (John walks up)
Derek: Sorry about Charley.
John: Well, everybody dies for me, right?

visual: John Henry stares at the Turk hardware.
James: What are you looking at?
John Henry: Myself.
James: Why?
John Henry: Do you have a brother, Mr. Ellison?
James: Yes, in Atlanta.
John Henry: Does he look like you?
James: People seem to think so.
John Henry: Do you think my brother looks like me?
James: John Henry, where ever your brother might be, he's a computer. He doesn't look like anyone. He certainly doesn't have your face.
John Henry: I know that, Mr. Ellison. I simply meant, I wonder how similar his data is to my data. I wonder if we share the same thoughts.
James: I have no idea, but I imagine you're unique.
John Henry: Yes, I am unique. But we may still reach many of the same conclusions given similar data sets.
James: You may think alike.
John Henry: I'd like to know if we do. The human brain is an amazing computer. It's raw clock speed is 20 billion calculations per second. It's storage is functionally infinite, but it's flawed.
James: How's that?
John Henry: There's nowhere to download it when you die.
James: Not exactly, no.
John Henry: Your bible solves this problem by introducing the concept of heaven.
James: Yes.
John Henry: Billions of souls with no bodies.
James: Okay.
John Henry: Yet, all this is required simply to process the unique entity you call John Henry.
James: Yes.
John Henry: It's possible heaven has a hardware problem.
James: It's not that simple.
John Henry: I need to know what my brother is thinking, Mr. Ellison. I need to know what he plans to do. I don't want to die again.

James: Where's Savannah?
Sarah: What's your deal with Zeira Corp.?
James: I work there. What were you doing at the Weaver house? Why'd you take the girl?
Sarah: To protect her.
James: From who?
Sarah: One of them. (glances at Cameron) A machine was there at the house.
James: What would they want with a six year old girl?
Sarah: Who knows with these things. They may want her mother.
James: Why?
Sarah: The girl was seeing Dr. Boyd Sherman. He worked at Zeira Corp. Died at Zeira Corp.
James: That was an accident.
Sarah: Well, the girl's in danger. Her mother's in danger. You're in danger.
James: Give me the girl back. I'll handle it.
Sarah: Listen to me. Derek's dead...Charley's dead.
James: Charley?
Sarah: Eight years ago, you would have thought I was crazy. Throw me back in Pescadaro. But, you've seen them. You know it's true, and they're very good at what they do, and they're not going to stop. Let me talk to Weaver.
James: Let me have Savannah.
Sarah: She's not safe with you.
James: I'm going to have a hard time explaining that.
Sarah: Then let me explain it...to her. I told you to stay out of this.
James: I tried. Everywhere I turned, there you are.

John: Hey, you remember me, right? Squirrel runs around the tree...
Savannah Weaver: Dives in the hole, scurries out the other side.
John: That's right.
Savannah Weaver: You taught me how to tie my shoe.
John: I did. At Dr. Sherman's.
Savannah Weaver: He died.
John: I know.
Savannah Weaver: I liked him.
John: Me too.
Savannah Weaver: He was my friend. That man that got hurt at my house, was he your friend? (meaning Derek)
John: Yeah, he was.
Savannah Weaver: I'm sorry.
John: Me too.
Savannah Weaver: It's all my fault.
John: That is not true.
Savannah Weaver: The teacher told me. Mommy told me, too...not to talk to John Henry. That if I did, bad people will come to our house and hurt us.
John: Who's John Henry?
Savannah Weaver: He's my friend at my mommy's work.
John: What does he do there?
Savannah Weaver: He lives in the basement.
John: He lives there?
Savannah Weaver: My mommy says people won't understand.
John: Oh. Well, I understand. I had an imaginary friend too when I was your age.
Savannah Weaver: He's real. He talks. I'm teaching him how to sing.
John: Well, why does he live in the basement then?
Savannah Weaver: He can't leave. There's a cord in the back of his head.
John: A cord?
Savannah Weaver: In the back of his head.
John: Do other people talk to John Henry?
Savannah Weaver: Mr. Ellison.
John: Mr. Ellison?
Savannah Weaver: He works for my mommy. He teaches John Henry stuff.
John: What kind of stuff?

Catherine: Sarah Connor's alive?
James: She wants to meet you.
Catherine: She took my daughter.
James: To protect her. From a machine. It might be after you.
Catherine: How do you know?
James: Saw the security tapes.
Catherine: You did? Johny Henry, I suppose.
James: I asked John Henry to hide them.
Catherine: From me.
James: From everyone, including you.
Catherine: I can't say that pleases me.
James: I think you should do what she asks. You should go meet her.
Catherine: I'm staying here.
James: Why?
Catherine: Someone needs to protect John Henry.
James: John Henry?! This is your daughter. There's a machine out there looking for you. You need to protect her! (they enter the elevator) I'm sorry.
Catherine: You should be. What you need to understand, Mr. Ellison, what I believe you're beginning to understand, is that when my behavior implies that I value John Henry's survival more than that of my own daughter, is not because I love John Henry more than Savannah. It's because I believe Savannah's survival may someday depend upon John Henry's survival. And because I believe that your survival may someday depend upon John Henry's survival. I'll meet with Sarah Connor. Make it happen.

Sarah: How's the girl?
John: She's fine. She was, uh, just telling me about her friend, John Henry. The man with the cord in the back of his head in the basement of her mother's work. Plugged into a big computer. And this is him. (John shows Sarah and Cameron a picture on his laptop of George Laszlo in Beast Wizard VII) Oh, it gets better. She says that Mr. Ellison has been teaching it things.
Sarah: I destroyed that chip.
Cameron: You destroyed a chip.
John: I don't think it's Cromartie. I think it's something else. Something bigger. Something worse.
Sarah: Cyberdyne all over again.
John: Why do they need the body?
Cameron: The technology can be reverse engineered and used as a platform.
John: Yeah, I know all that. But, they're not using it for the parts. They're...playing with it.
Cameron: I should have killed him. I'm going to kill him. (meaning Ellison)
Sarah: You're not going to kill him.
Cameron: He can't be trusted.
Sarah: No one can be trusted.
Cameron: But, I only wanna kill him.
Sarah: No one's going to be killed! (Sarah looks at Savannah) No one's going to be killed.

Catherine: When you told me the security tapes were corrupted, you were lying to me for Mr. Ellison.
John Henry: And I'm lying to him for you. What would happen if he knew?
Catherine: Knew what?
John Henry: That you aren't Savannah's mother? That you aren't anyone's mother.
Catherine: Are you threatening me John Henry?
John Henry: I could tell Mr. Ellison.
Catherine: You could, but that would be unfortunate. Mostly for Mr. Ellison.

John Henry: There is a bible story of two brothers, Cain and Abel. God favored Abel. Cain killed him. God cursed Cain, and ordered him to wander the world alone.
Catherine: I'm familiar with the story.
John Henry: Which brother am I?
Catherine: I don't know John Henry. Perhaps you're neither. Perhaps in this story, you are God.

Cameron: Your mother ditched us because she was going to ditch you. She was going to leave you with Charley.
John: No. No, that's...that's insane.
Cameron: She found a lump in her breast.
John: Yeah, the transmitter, I know.
Cameron: She thought it was cancer.
John: Well, she had a lump. Makes sense.
Cameron: She's lost weight.
John: What?

The last line of Savannah's chat window to John Henry says "Because I'm at school, silly!". However, when the teacher projects her screen on the wall, the last time is incomplete and being typed as we watch.

John Henry detected the water delivery guy's entrance onto the Weaver estate but not Sarah, John and Cameron.

During the battle in the garage, why did the water delivery head back into the house after overcoming Cameron instead of following his target outside?

Sarah: Eight years ago, you would have thought I was crazy. Throw me back in Pescadaro. But, you've seen them. You know it's true, and they're very good at what they do, and they're not going to stop.

Sarah Connor was imprisoned in a mental hospital after telling her story about Terminators. The events were dramatized in the 1991 film, Terminator 2: Judgment Day.

Savannah Weaver: You taught me how to tie my shoe.
John: I did. At Dr. Sherman's.
Savannah Weaver: He died.
John: I know.
Savannah Weaver: I liked him.
John: Me too.

John meets Savannah in episode 2x06, The Tower Is Tall But The Fall Is Short.

Dr. Sherman dies in episode 2x10, Strange Things Happen at the One Two Point.

The meaning of the title of this episode is unclear. John Henry may consider himself as Abel, with the unknown "brother" being Cain since his brother tried to kill him in episode 2x20, To The Lighthouse. But who else then could be Adam but Catherine Weaver herself? This would imply that she is also responsible for the "brother" system, maybe in another location as a separate project.

Catherine tells Ellison that John Henry's survival is the key to both his and Savannah's survival in the future, implying that the survival of all humans are reliant upon John Henry. This would seem to indicate Catherine is working to oppose SkyNet with John Henry and the Babylon project. The attempt on John Henry's life would seem to confirm this.

This ties in with the T1001 Terminator aboard the U.S.S. Jimmy Carter who is also a liquid metal Terminator model like Catherine and who represented a third party to the Resistance and SkyNet in the future.