Here is how Yuna, Dusty and Duck were missing! and the fantasy and FairyTale Railway goes in Fantasyland Rescue.
Meanwhile at Equestria and the Island of Sodor.
Princess Luna: Come on, Sister. Yuna, Dusty and Duck might be lost out there.
Princess Celestia: Something must be wrong.
Hiro: What is it?
Princess Celestia: Yuna, Dusty and Duck were missing!
Princess Luna: No!
Snowdrop: Are they... Gone?
Princess Luna: Yes.
Princess Celestia: We must search for Yuna, Dusty and Duck at once.
The next day, at Fantasyland.
Duck: (yawns) Huh? We're still on Fantasyland.
Princess Yuna: I can't be.
Dusty Crophopper: How?
Duck: We'll think of some way we can get home.
Princess Yuna: We could ask Casey Jr. and the others for their help.
Dusty Crophopper: Good idea!
Duck: Let's go.
Princess Yuna: Right behind you.
Dusty Crophopper: Wait for me!
Duck: Follow me!
At the Fantasy and FairyTale Railway Traction Company, Limited.
Princess Yuna: I just know they can help.
Dusty Crophopper: It's worth a shot.
Duck: There's hoping.
Princess Yuna: Look! There's Casey Jr., Toots, Tillie, Tootle, Montana, Emma, Puffle, Ivor, Jebediah, Georgia, Pete, Farnsworh, Alfred, Melissa, Tom Jerry, Azul, Greendale Rocket, Johnny, Doc, Jacob Pneumatic, Huey, Big Tim, Bonnie, Jason, Sir Reginald and Sasha!
Dusty Crophopper: And look! There's The Human Counterparts of the Mane 6, the CMC, Sunset Shimmer and Spike's Dog Counterpart.
Duck: Maybe they can help us.
Princess Yuna: Exactly the idea, Duck
Dusty Crophopper: Let's go ask them.
Duck: (whistles) Hello!!!
Human Twilight Sparkle: Hey, Yuna, Dusty, Duck.
Ivor: Great to see you three again.
Human Applejack: So, What brings y'all here?
Princess Yuna: We still have to find our way back home.
Tillie: Maybe we can help.
Toots: We can help each other.
Porky Pig: That's what friends d... friends d..... Friends are for.
Toots: What're we waiting for?
Little Tim: Let's go!
Katie the Caboose: We'll help you guys.
Tootle: No matter what.
Dusty Crophopper: Thanks.
Meanwhile, at Equestria and the Island of Sodor.
Princess Celestia: Have you any sign of them?
Thomas: No luck on them.
Skarloey: We've searched everywhere.
Princess Celestia: Go through these tunnels to find Yuna, Dusty and Duck on Sodor, Equestria, Dreamland, Disneyland and Animal Kingdom.
Toby: Right away, Princess Celestia.
Toad: Don't worry, Prince Hiro, Princess Luna. We'll find them.
Princess Luna: I hope so.
Hiro: Don't worry, Luna. I'm sure they're okay.
Princess Luna: As long as they're together. We must find them and get them back home.
Snowdrop: If only I can see them myself.
Back at Fantasyland.
Casey Jr.: So, All we have to do is find a way to get you guys back to Equestria.
Montana: The question is Which way we have to go?
Duck: The Great Western Way or the Wrong Way.
Azul: Either way, We'll get them home.
Greendale Rocket: Right, Azul.
Azul: Which way do we go?
Dora the Explorer: Let's check on every dock in Fantasyland.
Boots: Great idea, Dora.
Azul: Maybe we can get you guys home that way. Com on.
Princess Luna: (in her royal Canterlot voice) YUNA?! DUSTY?! DUCK?! WHERE ARE YOU?!
Snowdrop: DUSTY!? DUCK!?
Tigatron: YUNA!? WHERE ARE YOU!?
Airazor: Where could they be?
WALL-E: (searching around Ponyville)
EVE: (searching around Canterlot)
Rainbow Dash: Hey! Where are you three!?
Lightning Storm: YUNA!? DUSTY!? DUCK!?
Thunder Spectrum: Yuna!?
Blue Star: Dusty!?
Fluttershy: Yuna? Dusty? Duck? Are you there?
Arachna: Where are you?
Dragonsly: Where did they go?
Humblebee: Keep Looking!
Pinkie Pie: Yuna? Dusty? Duck? Are you out here?
Hoof Trooper: Keep Lookin' Cadets!
Red Beret: We're on it, Pop!
Brownie: Still Looking!
Applejack: Yuna? Dusty? Duck? Are y'all there?
Apple Bloom: I don't see them anywhere.
Copper: Ain't no way they're in Sweet Apple Acres.
Golden Apple: I hope they're okay.
Rarity: Yuna? Dusty? Duck?
Spike: Where are you three?
Princess Twila: Yuna? Dusty? Duck? Where are you?
Princess Lilly Sparkle Rose: Where are they?
Flash Sentry: Yuna? Dusty? Duck?
Princess Skyla: Mommy, Daddy, I missed Yuna.
Princess Cadance: (comforts her daughter) We know, Sweetie. We missed them too.
Shining Armor: Come on, Let's keep looking.
Derpy Hooves: Come out, come out, wherever you are.
Octavia: Yuna? Dusty? Duck?
DJ Pon-3: Yo! Yuna? Dusty? Duck? Where are you?
Twilight Sparkle: Yuna? Dusty? Duck? where are you .
Everypony: YUNA?! DUSTY?! DUCK?! We miss you!
On the Island of Sodor.
Harold the Helicopter: I've looked all over Sodor, Sir. There's still no sign of Princess Yuna, Dusty and Duck.
Sir Topham Hatt: Dose anyone else found them yet?
Captain: They're not at Brendam Docks.
Bash: Not even...
Dash: ...Misty Island.
Ferdinand: That's right.
Mavis: We've searched every Quarry.
Whiff: And every Garbage Disposing area.
Scruff: We're sorry, Sir. We couldn't find them in Sodor.
Sir Topham Hatt: If they'r not in Sodor. Then, They must be in Dreamland. Captain, Take me there as fast as you can!
Captain: Full steam ahead!
Rusty: Where they go?
Tracy: Let's keep looking!
Patrick: Right behind ya, Tracy!
Humphrey: Yuna? Dusty? Duck?
Roderick: Where are you guys?
Minevra: Oh, Where could they be?
Tower (female): Have you any sign of them?
Tracy: They're not in Dreamland.
Rusty: Where else could they be?
Shelbert: I have no idea.
Tracy: Maybe, They're in Disneyland. Let's look here.
Mickey Mouse: Where are Yuna, Dusty and Duck?
Donald Duck: I don't see them anywhere!
Goofy: Gawrsh, I hope they're okay!
Oswald the Lucky Rabbit: Me too!
Pete: Well, Come on, Let's keep looking!
Minnie Mouse: Yuna? Dusty? Duck?
Daisy Duck: Where are you?
Sylvia Marpole: Boys, Any sign of them?
Max Goof: Nope.
PJ: No sign of them!
Bobby: No luck!
Mona: Elsa, Have you and the others found them?
Elsa: My goddaughter is gone. Where could she be?
Anna: Don't worry, Elsa. We'll find her and Dusty and Duck.
Olaf: I hope they're okay.
Kristoff: Me too. (speaking Sven) Me three!
Sven: (thinking as Kristoff thought)
Gremlin Gus: Hiro, Woody, Ralph. Have you found them yet?
Hiro Hamada: No
Baymax: There's still no sign of Princess Yuna, Dusty Crophopper or Duck.
Fred: Yuna? Dusty? Duck?
Wasabi: Where are you guys?
GoGo Tomago: No luck!
Honey Lemon: They're not here!
Woody: Keep looking.
Buzz Lightyear: Yuna! Dusty! Duck!
Jessie: Come on, Bullseye! Let's keep searching!
Bullseye: (keeps looking)
Rex: Oh, where could they be?
Hamm: Not a clue.
Mr. Potato Head: I hope they're okay.
Mrs. Potato Head: Me too.
Slinky Dog: Yuna? Dusty? Duck? Where are you?
Woody: Have you guys found them?
Buttercup: Still no luck.
Mr. Pricklepants: We've searched everywhere.
Dolly: Still no sign of them.
Trixie the Triceratops: I hope they're okay.
Chuckles the Clown: Me too.
RC: (vrooming; translate, "Same here")
Wreck-It Ralph: Yuna? Dusty? Duck?
Vanellope Von Schweetz: Are you guys there?
Fix-It Felix, Jr.: Are you here? Hello?
Ishani: Lightning, Any sign of them?
Lightning McQueen: No. They're not at Radiator Springs.
Mater: We're really sorry, Miss Ishani.
Finn McMissile: We've searched all over Dusty's home.
Holley Shiftwell: Still no sign of them.
Sally Carrera: I hope they're okay.
Luigi: Princess Yuna? Dusty? Duck?
Guido: Dove sei? (Translate Where are you?)
Ramone: Hey! Where are you!?
Flo: Yuna!? Dusty!? Duck!?
Fillmore: So far, No luck on finding them, Man.
Sarge: We better keep looking!
Sheriff: Anybody else had any luck on them?
Chug: Nope. No luck, Sheriff.
Dottie: We couldn't find them anywhere.
Sparky: I hope they're okay.
Skipper Riley: We better keep looking.
Bulldog: They could be in the Animal Kingdom.
El Chupacabra: Our Amigos will know what to do.
Rochelle: I hope so.
Blade Ranger: Where could they be?
Li'l Dipper: They're not at Piston Peak National Park.
Windlifter: The Smokejumpers search high and low and no sign of any of them.
Cabbie: We better keep looking.
Mayday: Let's hope they'll make it.
Rex: Hey, guys! I think we found them! Yuna? Dusty? Duck? Is that you three?!
Rex: Whiskers?! Will you get out of here?! We are trying to find our missing friends!
On Animal Kingdom.
Princess Luna: Any sign of them? simba can you see yuna dusty and duck around pleasss
Simba: We've looked all over the Pride Lands there still no sign of the them luna and hiro im so sorry.
Timon: We even looked in our Paradise.
Pumbaa: Still no sign of them.
Nala: We're really sorry, Princess Luna have you seen them kiara and kovu .
Kiara: well we 've search everywhere mom We've searched the Elephant Graveyard. have you seen them kovu
Kovu: (nods nope) uh nope kiara there Still no sign of them.
Hiro: You all did what you've could to help find them.
Princess Luna: I hope they're alright.
Hiro: Me too, Luna.