This was the last episode produced before the WGA strike. Actress Katee Sackhoff said that if the strike had lasted long enough, the episode would have wound up serving as a series finale.

The last Cylon is revealed: Ellen Tigh.

This episode marks the death of Anastasia Dualla.

Kate Vernon's name is withheld until the closing credits to maintain the surprise revelation of the ending, although she has been listed in the opening credits following her character's death before.

Roslin: It's perfect. We traded one nuked civilisation for another.

Roslin: So the Thriteenth Tribe settled here and created their own Cylons.
Lee: Then the machines rose up and killed their masters.
Baltar: That's what we thought. Until we tested the bones.
Number Six: 250 skeletons so far, from four different sites on the planet. Using your protocols...
Baltar: The results are conclusive.
Adama: What's your point?
Tigh: They're not human. They're Cylon.
Adama: All of them?
Tigh: All of them.
Baltar: The Thirteenth Tribe was Cylon.
Tigh: The Thirteenth Tribe, the tribe of Cylons, came to this planet and called it Earth.

Kara: If my Viper's splattered all over this planet, then who flew it here and what the hell did I fly back to Galactica?
Number Two: Maybe it's better off not knowing.
Kara: You're always telling me to face the truth and not run from it. Why the sudden change of heart?
Number Two: I've got a feeling. You might not like what you find.

(after appearing to find her own dead body)
Kara: If you've got an explanation for this, now's the time.
Number Two: I - I don't have one. I was wong... about Earth.
Kara: Your Hybrid told me something. Said that I was the harbinger of death, that I would lead us all to our end.
Number Two: She told you that?
(Leoben backs away and runs)
Kara: Is it true? Is it true? If that's me lying there, then what am I? What am I?! What am I?

Adama: Ah, Ellen. Yeah, you know, Ellen was smarter than I gave her credit for.
Tigh: Don't go there, Bill.
Adama: Smarter than me. She knew from the beginning that there was something wrong with you.
Tigh: What?
Adama: That's why she went around frakking half the Colonial fleet.
Tigh: Shut your mouth!
Adama: Searchin' out, tryin' to find a man who had real blood in his main vein.
Tigh: Shut your frakking mouth!
Adama: She came on to me once. Like a dog in heat. I could smell. I could smell it. She smelled so good.
(Tigh puts a gun to Adama's head)
Adama: Go on, do it. Do it. Do it! (puts a gun to his own temple) Or I will. Go on! Go on! Do it. Go on.
Tigh: Oh my Gods. That's why you came here. To do this. You haven't got the frakking guts to do it yourself. (removes ammo from gun) I'm sorry, Bill. This is one time I can't help you.

Adama: Men and women of the fleet, this is the Admiral. The discoveries of the past few days have been painful for all of us. As you know, we cannot stay on Earth. But this is not a new challenge. The Thirteen Tribes of Kobol stood exactly on the same spot that we are right now. They experienced dreaful losses. Their planet was a graveyard. They needed a home. So they set out in the void of deep space with nothing but their ships and their guts. And the Thirteen succeeded. They weren't supermen. They were ordinary people, like us. What they can accomplish, we can accomplish. We will find a new home. This is a promise I intend to keep.