Here is how The Cutie Mark Crusaders became the Cabin Fillies and Merlock makes his plan in The Tale of The SquarePants Master Ship Builders.
Applejack: Apple Bloom!?
Rarity: Sweetie Belle!?
Rainbow Dash: Scootaloo!?
Mickey Mouse: What're you girls doing here?
Apple Bloom: (panting) It's Dijon and Gremlin Prescott.
Sweetie Belle: (panting) They were trying to steal the Elements of Harmony.
Scootaloo: We got them just before they were going to take it away from the Tree of Harmony.
Apple Bloom: (brought out the Elements of Harmony and the pictures they took as proof)
Patrick Star: WHAT?! That's insane.
Titanic: Oh dear!
Olympic: It must be the work of Merlock the Sorcerer!
Titanic II: He must be on the move to seek his dark purpose!
Titanic: Not to worry, Little ones. You three are safe now.
Gremlin Gus: (horrified) I can't believe Prescott was working for Merlock!
Panchito: ¡Dios mío! (My goodness) This must be serous!
Oswald the Lucky Rabbit: I'll say it is!
Mickey Mouse: I'm glad you girls came with us. No going back now.
Rarity: You girls could be a use at the S.S. Headliner.
SpongeBob SquarePants: Hey, guys. Look! The first new element of harmony must at the iceberg that the RMS Titanic hits. The second new element must be at the Pride Lands. The third new element should be at the Great Valley.
Titanic: (remembers the iceberg that she hits when as a ship)
SpongeBob SquarePants: Titanic? Are you okay?
Titanic: I'm fine, SpongeBob.
Olympic: She remembers that time when she was the RMS Titanic.
Plankton: No kidding.
SpongeBob SquarePants: Should I talk to her?
Britannic: No need, SpongeBob. She'll come around eventually.
With the CMC.
Apple Bloom: Well, This is hard work.
Scootaloo: Yeah, Never actually thought we'd be Cabin Fillies.
Sweetie Belle: Maybe can earn our cutie marks that way.
Apple Bloom: Not a bad idea, Sweetie Belle.
Scootaloo: Than that makes us the Cutie Mark Crusaders Cabin Fillies.
Sweetie Belle: Yeah. Sweeping....
Apple Bloom: Moping....
Scootaloo: Doing the dishes....
Sweetie Belle: And washing windows.
Apple Bloom: Going on an adventure is fun when we're Cabin Fillies. We'll leave no stone unturned!
Scootaloo: No mountain unclaimed!
Sweetie Belle: No meal uncooked!
CMC: Cutie Mark Crusaders! Cabin Fillies! Yeah!
Squidward Tentacles: Apple Bloom! Sweetie Belle! Scootaloo! Would you please keep it down!?
Scootaloo: Sorry, Squidward!
Merlock: YOU FOOLS!!!
Dijon: We're sorry, Merlock.
Gremlin Prescott: It wasn't our fault!
Merlock: Then give me one excuse any of you have!
Dijon: It's because of three fillies, Master!
Gremlin Prescott: And they called themselves the Cutie Mark Crusaders.
Merlock: Do you at least know where they're going?
Dijon: They're going to a frozen iceberg.
Gremlin Prescott: That's where the first new element of harmony is.
Merlock: Then, We'll let them lead us to it. (use his talisman and turns into a griffin) Let's go!
Dijon: Yes, Merlock!
Gremlin Prescott: Let's hope we'll gather them that way!
And they took off.