Here's how Nightmare Moon & King Sombra talk to Blythe's conversation and the rescue plan goes in Attack of the Clone Equines.
[It sideswipes to the next scene and Nightmare Moon & King Sombra go to the prison cell of the Geonosian castle, and there was Blythe Baxter]
Blythe Baxter: You!
King Sombra: Blythe Baxter. Welcome to our little hideout.
Blythe Baxter: Why are you trying to kill Sunset Shimmer?
Nightmare Moon: Because, that traitor is nothing but a backstabber.
Blythe Baxter: She's more powerful than you think!
Nightmare Moon: [laughs] Oh, really. Maybe I should test her Lightsaber skills if she comes to rescue you.
Blythe Baxter: She'll beat you up.
King Sombra: But on to important matters. Why are you all the way out here?
Blythe Baxter: I'm looking for a bounty hunter, named "Rogue". Is he here?
King Sombra: There's no bounty hunter here. The Geonosians don't trust them.
Blythe Baxter: He is here. I can assure you.
Nightmare Moon: What if we told you that something far more worse is coming?
Blythe Baxter: That's not true, the Jedi would be aware of it.
King Sombra: If that's so. What if we told you all about a new war that is coming, a new Sith lord, and and old enemy returning?
Blythe Baxter: I don't know.
King Sombra: Join us, Blythe. And we can stop it!
Blythe Baxter: I'll never join you.
[Soon the 2 begin to leave but Nightmare Moon stops and looks back]
Nightmare Moon: We'll be seeing you later, darling.
[It sideswipes back to Canterlot with the others making a rescue plan]
Barret Barricade: Alright, listen up. This mission is very dangerous.
Shining Armor: I've been through many dangerous missions before.
Barret Barricade: But this one is very dangerious compared to others ones we've been on.
Eddy: Oh, please! I'm ready for anything that gets in my way!
Cadance: We've just received word from Blythe Baxter that she's gonna be executed.
Sunil Nevla: Executed?
Zoe Trent: NO!! We can't let that happen to her!
Penny Ling: Do we have a plan to stop all this?!
Princess Celestia: We shall have no choice. We'll have to get that Clone Equine army to rescue Blythe.
Brian: It's done then. We will head to Geonosis and rally every Jedi we know to rescue, Blythe.
Princess Luna: We'll visit, with the Clone Equine army. May the Force be with you.
[Brian nods and he walks away]