Here is how SpongeBob discovered the secret of the new Elements of Harmony and Merlock plans his Dark Purpose in The Tale of The SquarePants Master Ship Builders.
Jiminy Cricket: (narrating) After the ceremony, SpongeBob was on deck testing the wait the ship would carry. The S.S. Headliner was in the water. It was still an empty shell and SpongeBob as waiting for carpenters, engineers and painters to add boilers, engines, funnels and other things for the ship. Until....
Ten Cents: (has the rope on the S.S. Headliner)
Theodore Tugboat: Everything will be all set for the S.S. Headliner to be painted, SpongeBob.
SpongeBob SquarePants: Okay. Thanks, Theodore! (notice a glow on the captain's deck)
The crane fitted the four funnels on The S.S. Headliner.
Olympic: I wonder how SpongeBob is doing on his ship.
SpongeBob SquarePants: Princess Celestia! Princess Luna! I found something on the Ship! (shows the book of the new Elements of Harmony)
Princess Celestia: What is it?
Princess Luna: The Book of the new Elements of Harmony!
SpongeBob SquarePants: And look, It show's a map!
Princess Luna: I wish Hiro was here to see this.
Princess Celestia: I wish Duck was here too.
Dijon: That's right, Merlock. SpongeBob has found the Book of the New Elements of Harmony!
Merlock: Excellent. Soon, All in Equestria will be mine at last!
Dijon: Oh, Yes, Merlock. Everything will be at your command!
Merlock: Yes. Prescott. Find the Tree of Harmony and bring the first elements to me.
Gremlin Prescott: Yes, Merlock.
Merlock: And make sure you keep watch for SpongeBob.
Gremlin Prescott: Consider it done.
Back at the SquarePants Master Ship Builders.
The S.S. Headliner was painted and the flags and steering wheel is set. When it was in the dry dock, SpongeBob met up with Captain Stubbs and his crew who're almost finish.
Mr. Pym: (guiding the crane lowering the one of the propellers on the S.S. Headliner) Keep her coming. Lower. Easy. Easy does it.
Captain Stubbs: How're the flags coming, Helga.
Helga: All set, Captain.
Jiminy Cricket: (narrating) The S.S. Headliner was in the dry dock and the workers finishing the ship.
Mr. Pym: We're all set, Eugene.
Mr. Krabs: That's great, Mr. Pym. SpongeBob, Are you sure about the new Elements of Harmony?
SpongeBob SquarePants: I'm sure, Mr. Krabs. And this book shows a map as proof. You believe me. Right, Gary?
Gary the Snail: (meows)
Patrick Star: The S.S. Headliner is gonna need a brand new crew.
Donald Duck: Hello.
Oswald the Lucky Rabbit: Maybe we can help.
Goofy: We know a few friends who can form a crew with us.
Gremlin Gus: Donald, Goofy, Oswald and I volunteered as mates to the S.S. Headliner.
Mickey Mouse: And I'll be the captain.
Gary the Snail: (Meows)
Twilight Sparkle: We're with you, SpongeBob. We'll find us a crew for our voyage for the new Elements of Harmony.
SpongeBob SquarePants: Great, We'll leave tomorrow at dawn. Are you ready, Gary?
Gary the Snail: (Meows)
Oswald the Lucky Rabbit: Ortensia, Don't worry. I'll be alright.
Ortensia: I love you so much, Oswald.
Oswald the Lucky Rabbit: I lover you too.
Daisy Duck: Be careful, Donald.
Donald Duck: I will, Daisy.
Goofy: Ready, Max?
Max Goof: Ready, Dad.
Sylvia Marpole: Good luck for tomorrow, Boys.
Minnie Mouse: Safe trip, Mickey.
Mickey Mouse: Thanks, Minnie.
With Merlock, Dijon and Gremlin Prescott.
Merlock: Alright, We must find the first Elements of Harmony.
Dijon: We can search in the Everfree Forest.
Gremlin Prescott: Of course. The Everfree Forest.
Dijon: We'll find the Tree of Harmony.
Gremlin Prescott: Exactly. We're ready when you are, Merlock.
Merlock: Go, And do not fail me.