Later that evening, the engines were getting ready for sleep at Tidmouth Sheds. Gordon, Henry, James, Donald and Douglas normally slept there, sometimes with Edward, Duck, and Emily. Tonight, however, Edward was sleeping at Brendam with Bill and Ben, Duck was sleeping at Arlesburgh with a tank engine named Oliver, and Emily slept on her own Knapford Sheds.

In their places were Thomas, Percy and Toby, who normally slept at the branchline sheds at Tidmouth, but they were undergoing repairs so they were welcomed here at Tidmouth. Tonight would've been peaceful, but a certain red tender engine was moaning about his miserable day…

"What a day I've had to suffer!" James grumbled, "First I have to take a goods train, then I get shut up in the sheds, then I go to the quarry, then Harold dirties my paintwork, and now people had to laugh at me! It's disgusting!"

"James, would you do us a favor and shut up?!" Henry yelled in frustration, "I swear, your paintwork is all you complain about!"

"At least I don't need special coal to steam properly!" retorted James.

"You can both shut up," snapped Thomas, who was getting annoyed, "for big engines, you're acting like little tank engines!"

"Take that back!" argued Henry.

"Don't speak to him like that!" retorted Percy, "If I wasn't in steam—!"

"All four of you, be quiet!" Toby shouted angrily, "I'm ashamed of you; acting so childish! Every engine needs his or her sleep, and arguing with each other isn't helping."

"If my paint was nice and shiny—"

"Well, the fact is, it isn't James. I'm sure you'll get a wash first thing in the morning. We have a long day ahead of us after all."

"I certainly hope so," James groaned.

"Aye, we best lighten oop," said Donald, "cause I hear someone coomin' in."

"Who might that be?" asked Douglas.

That someone was Miss Celestia. She was wearing light purple colored pajamas. Fortunately for the engines, she hadn't heard the argument.

"I'll be spending the night here," she told the engines, "that way, I can keep an eye out in case Diesel 10 comes around for trouble."

"Thank goodness for that," remarked Gordon.

Before long, the engines were fast asleep, but Miss Celestia was awake on a makeshift bed she had made.

"Nothing like a bedtime drink of hot chocolate," she said to herself. She held a mug in one hand, a thermos of hot chocolate in the other.

Unbeknownst to her and the engines, Diesel 10 had sneaked up beside the sheds.

"Alright, boy," said Discord, "time to feast your little bucket of badness!"

Right now, Tidmouth Sheds were subject to repairs as well. A piece of tarpaulin swung loose from a ladder at one end. Diesel 10's roof opened to reveal his claw, and Discord positioned it to grab the tarpaulin.

Miss Celestia tasted her hot chocolate, and then frowned.

"Just a little sweeter, I think…"

She poured in a spoonful of sugar, and then tasted it again.

"Ah! Now that's better."

All of a sudden, Diesel 10's claw yanked the tarpaulin off! Debris flew everywhere!

"Bust my buffers!" cried Thomas, who had woken up, "It's Diesel 10!"

"Diesel 10-?! Oh no!"

The other engines had woken up as well, and they gaped in horror as the villains cackled.

"Long time, no see, Celestia!"

"Discord…" Celestia glared angrily.

"We've got a plan, and you're not in it!"

Diesel 10 moved his claw in for the kill.

"You can't catch me, Diesel 10!" Celestia cried as she grabbed her conductor's whistle and blew it. But instead of disappearing, she only sparkled for a bit. Surprised, she tried again, but got the same results.

Diesel 10 cackled again. "Losing your sparkle, eh? Ha ha ha! What perfect timing!"

Just as it seemed she was trapped, Celestia quickly grabbed the bag of sugar and held it up to Diesel 10 as if she were holding a cross up to the devil himself.

"Agh!" cried Diesel 10 in terror, "Is that-?!"

"That's right, it's sugar, Diesel 10!" Celestia said firmly, "And if I pour this in your tank, it'll seize you up for good!"

"What's going on here?"

At that moment, they heard the sound of a diesel horn, and a long green diesel with a Co-Bo wheel arrangement came in from the distance pulling a night goods train. This diesel is BoCo, a friend of Edward and the tank engine twins.

"And why, pray tell, are you attacking my friends, Diesel 10?" BoCo asked sternly.

"These puffballs are your friends?!" Diesel 10 snapped, "Traitors like you shall pay for your insolence someday!"

"You'll be the one paying for threatening them if you don't get a move on," retorted BoCo firmly, "now beat it, or else I shall report you to the authorities, and they'd love a good talk with you."

As much as they loved bothering the steam engines, Diesel 10 and Discord agreed they did not want to deal with the authorities. So they backed off.

"Make the most of tonight, Twinkle Toes," Diesel 10 snarled, "because you won't like tomorrow!"

"Nor will those tin kettles!" Discord called in agreement. BoCo watched as the clawed diesel rolled away.

"Is everyone alright?" BoCo asked with concern.

"We're alright now, BoCo," said Thomas, "just a little shaken up."

"Well, I better tell the workmen about this," said BoCo, setting off, "they won't be happy…" And he rumbled away with his trucks clattering behind him.

After he'd left, Celestia looked at her whistle.

"Miss Celestia, but what happened to your sparkle?" asked Thomas.

"I don't know, Thomas. I'll have to sleep on it."

"On your sparkle?" Thomas asked, confused.

"No, Thomas… but on the problem of what happened to it…"

"But Miss Celestia," said Percy, "without your sparkle, you won't be able to help us anymore…"

"Not only that," put in James, "but you might not be able to hide from Diesel 10 and Discord."

"I'll solve the problem," said Celestia reassuringly, "you just go to sleep now."

"Easy for you to say…" Percy muttered as he went to sleep.

Meanwhile at Muffle Mountain, Chrysalis had returned with a pickaxe.

"They think they can hide that engine from me?" she sneered, "I'll show them!"

Then she began to dig away at the landscape. While she dug, she didn't notice Flash Sentry and his horse nearby. The horse sensed danger and backed away.

"That must be the motorcyclist Gordon warned me about," Flash said to himself. With that, he rode back towards the nearest station. Thankfully, Chrysalis hadn't noticed him.

Flash rode all the way to Peel Godred where Big Macintosh was making a nightly delivery of apples.

"Big Mac!" he called, "I saw a woman digging in Muffle Mountain for something. I have a feeling she's the stranger Gordon warned me about."

"Chrysalis?"

"I believe so," replied Flash, "I was lucky she didn't spot me."

"Thanks fer tellin' me," said Big Macintosh.

Winona, who was with Big Macintosh as the time, started barked in the direction of Muffle Mountain again.

"What's with Winona?" asked Flash.

"No idea," said Big Macintosh, "Applejack says she was doing that earlier in the day."

"You don't think this has anything to do with Shining Armor and Cadance, do you?"

Back at Tidmouth Sheds, everyone was asleep once again, even Celestia. Unfortunately, no one realized that Diesel 10 had crept back. His claw was holding a funnel of ash, and it moved along until it was directly over Thomas' funnel. Through the broken roof, ash poured into Thomas' funnel, but he was too fast asleep to notice.

Suddenly, Celestia began mumbling in her sleep.

"Sparkle… gold dust… magic… buffers… railway… buffers…"

Diesel 10 heard the word "buffers" and eased off to listen more. The noise startled Percy, who woke up in time to hear the word "buffers" again.

"Gold dust… valley… family…" Celestia continued mumbling. As she stopped mumbling, a dream came to her…

The figure of a mysterious person could be seen. Right above the person were six floating orbs. As they glowed, the person sparkled and decomposited gold dust on a bush on Muffle Mountain, along a trail from the mountain and through a meadow as beautiful flowers began to grow.

"The family told me," said Celestia's voice, "as long as there's a railway, there will be energy… As long as there is gold dust, there will be harmony… The family told me we have made sure that our railway is safe, we have made sure our gold dust will last forever, and you will never have to worry…"

Another vision showed what looked like Knapford Station, but abandoned and left to ruin. The rails were ripped up and in their places were smooth roads.

In a huge pile, at Vicarstown, lay the scrapped remains of all the steam engines, each one looking as miserable and lifeless as the next – a very heartbreaking sight.

Overlooking the remains of this once beautiful place was Pinkie Pie. Her hair had fallen straight and flat, and she had the most miserable face you could ever see.

"The magic is all gone…" she said sadly as a tear fell down the side of her face; she almost wanted to cry.

Suddenly, Celestia woke up in shock.

"What's gone wrong with our railway…? Our universe is in great danger – I've got to find more gold dust! I hope someone can help us out…!"

The following morning, the engines prepared to get ready for their jobs of the day. Henry had left earlier that morning to pull the Flying Kipper. James, however, was still upset.

"I'm such a filthy mess," he groaned.

"Here he goes again…" Donald muttered quietly.

At that moment, Rarity arrived.

"Good morning, engines," she greeted, "Miss Celestia… what's happened to the shed wall?"

"We received a nasty visit from Diesel 10," Miss Celestia explained.

"I see… Oh my stars, James! Look at your red paint!"

"I know," said James mournfully, "I'm a disgrace to splendid engines everywhere!"

"Over-acting wimp," muttered Gordon. No one had heard him.

"Miss Celestia," said Rarity, "would it be alright if I offered to clean James before his first trains of the day? We wouldn't want him to be dirty for his passengers, would we?"

"We engines get dirty every day," muttered Douglas.

"As long as you don't mind getting dirty yourself," Miss Celestia said, "then yes, you may clean James."

"As much as I dislike being dirty, I must help my friend," Rarity said determinedly.

With that, she set of to fetch a scrub brush, a ladder, and some soapy water. Whilst Rarity cleaned James, Miss Celestia gave the other engines their jobs.

"Gordon, express duties as usual today," she began, "James, you're in charge of the local service after you're clean. Percy and Toby have coal train duties while Douglas is doing Percy's mail runs. Donald, you're taking a goods train to Vicarstown. Thomas, you and Emily have branchline passenger duties."

Soon, the engines began to set off for work whilst Rarity continued cleaning James fast as she could, since cleaning locomotives was not an easy task. As the engines went about their work, Thomas' whistle sounded, but it didn't sound right to him…

"That's odd," murmured Thomas, "my whistle was fine the day before…"

"That noise is just dreadful," groaned Rarity, sticking a finger in her ear, "you can't go out if your whistle sounds like that, can you?"

"It's not very safe to do so," added James. Then he noticed Miss Celestia looking rather tired.

"Miss Celestia, why do you look so tired?" he asked, "Is it because I'm red? Diesel 10 says red is a very tiring color, but red looks so nice against the snow…" Then he had a terrible thought. "It's not me, is it?"

"Oh, no, of course not James," Miss Celestia replied kindly, "I think that red is bright and cheerful."

"Oh, thank you."

"Just like my sparkle… or at least it was, and it must be again…"

Miss Celestia seemed to be thinking for a bit when a thought struck her.

"Oh, I'm sorry, James; I've got to go to Crovan's Gate to search for something important," she said at last.

"Would you like one of us to take you there?" Thomas asked.

If Diesel 10 sees me riding in Thomas, Miss Celestia thought, he would know I'm out of gold dust, and that would be a dreadful thought…

"I think I'll be fine sparkling there, Thomas," Miss Celestia said at last, "but I think it would be best if you went along just to make sure. Daisy shall do your work today."

With that, she sounded her conductor's whistle, and after some difficulty, sparkled out.

By that point, James' paint shone once more. "Finished at last," said Rarity triumphantly, "there you go, James; shiny and clean once again."

"Thank you, Rarity," James smiled, "now I'm a splendid engine once again." And with that, he puffed onto the turntable once it was positioned for him. As James left, he heard a sneeze…

"ATISHOO!"

The sneeze had come from Thomas, and ashes had flown out of his funnel.

"Say it, don't spray it, Thomas," James said. The ashes landed close to James, but fortunately, they didn't get him dirty.

"Sorry," coughed Thomas, "still got ashes in my funnel…" He sounded his whistle; it was the perfect pitch.

"Now that's better." And with that, Thomas set off as well.

Crovan's Gate is the terminus between the North Western and Skarloey Railways, where the narrow gauge engines live and work. Nearby the station was the Steamworks where the engines go for repairs, overhauls, or restoration. Although it was called the Sodor Steamworks, diesels have been repaired there as well.

The Skarloey Railway is home to five tank engines, one diesel, and one tender engine. The first tank engine is a 0-4-2 saddle tank painted red with white and gold lining; his name is Skarloey. The second tank engine is a 0-4-0 well tank painted vermilion with gold and black lining; his name is Rheneas. The third tank engine is a 0-4-2 saddle tank painted blue with red and yellow lining; his name is Sir Handel. The fourth tank engine is a 0-4-2 saddle tank painted dark green with red and yellow lining, and unlike Skarloey and Sir Handel, he had a Giesl Ejector funnel; his name is Peter Sam. The fifth tank engine is a 0-4-0 well tank painted yellow with black and gold lining; his name is Duncan, the Skarloey Railway's number six. The railway's diesel is painted orange with yellow lining and white lettering; his name is Rusty, named for Ruston and Hornsby, and is the railway's number five.

The railway's tender engine is a 0-4-0 saddle tank and tender painted brown with yellow lining, and has two red plaques on either side of his saddle tank with the word "DUKE" in gold. This engine is Duke, named after his grace, the Duke of Sodor. Years before, he, Peter Sam and Sir Handel worked on their own little railway far from the Skarloey Railway. Back then, Peter Sam was called Stuart and Sir Handel Falcon, named for their respective locomotive works, but they like their new names better. Unlike Rusty and the five tank engines, Duke has no official number.

Sometimes a trio of pre-teen girls came to the sheds to share their adventures, listen to stories, or just help in cleaning the engines. Apple Bloom is a girl of eleven with bright red-rose hair, gamboge eyes, a light crimson bow in her hair, wore a green T-shirt, blue denim overalls, and orange boots. Her real name is Blossom Apple-Smith, and she's the younger sister of Applejack and Big Macintosh. Apple Bloom's best friends are Susie "Sweetie" Belle, Rarity's little sister, and Scottie Lou "Scootaloo".

Sweetie Belle is a girl of eleven with grayish mulberry hair with grayish rose streaks, pale green eyes, wore a magenta short sleeved jacket, a white tank top with pale rose horizontal stripes, a purple waist belt, a long pale yellow skirt, and rose-colored shoes. Scootaloo is a girl of twelve with cerise hair, grayish purple eyes, wore a white t-shirt underneath a dark gray short sleeved hoodie, dark green shorts, and black boots. She had a blue plank on four wheels with a handlebar attached, giving her the nickname "Scootaloo."

Together the three girls are known as the Cutie Mark Crusaders.

Back to our story; the waterfall Miss Celestia had mentioned earlier was located beyond Crovan's Gate close to one of the stations on the Skarloey Railway. Edward had arrived at Crovan's Gate with a stopping passenger train.

"Hello, Edward," said Skarloey, "how are things on the Fat Controller's railway?"

"BoCo told me that Diesel 10 attacked Tidmouth sheds last night," Edward explained.

"That's wrong!" cried Rheneas, "That Diesel 10 is a right bully, he is, from what I heard."

"What's important," said Duke wisely, "is that we all stand up on our wheels against Diesel 10."

"You're right, Duke," said Edward, "it's lucky he doesn't know that the lost engine of the legend really exists."

"What engine?"

"What legend?"

"What're ya'll talkin' 'bout?"

The engines looked and noticed the Cutie Mark Crusaders, who had heard everything.

"Should we tell them?" Rheneas whispered to Skarloey.

The engines looked at the trio as Skarloey cleared his throat. "The legend of a steam engine whose magic makes her more powerful than Diesel 10 could ever be," he explained, "very few have seen her."

"It's been said that she's the reason Sodor is the way it is," added Rheneas, "if anything bad were to happen to her, life as we know it would cease to be."

"That is why it's important that Diesel 10 never discovers her existence," finished Edward.

"Then we should find her first," said Peter Sam.

This gave the Cutie Mark Crusaders an idea.

"Maybe we should look for that lost engine," suggested Scootaloo.

"Ha! Three kids like you finding a lost engine?" laughed Duncan, "Please."

"Duncan, don't be rude to them!" Rusty hissed.

"Ya actually think we can't do it?" Apple Bloom sounded insulted.

"Well, not to sound rude," said Sir Handel, "but how are you even going to find the lost engine? You don't know where she is; no one does."

"Sir Handel!" scolded Rusty.

"What? I'm just saying."

"Well, I still think it would be a fun adventure," said Sweetie Belle, "so what are we waiting for?"

"Cutie Mark Crusader Engine Rescuers! YAY!" The three girls jumped into the air and gave each other high fives.

The engines simply chuckled; these three were always going on silly adventures. At that moment, Miss Celestia sparkled into view. The narrow gauge engines and the Cutie Mark Crusaders were surprised.

"Miss Celestia, madam," said Skarloey, "this is a surprise."

"What brings you here?" asked Rheneas.

"I need to get to the waterfall at Rheneas," explained Miss Celestia.

"He's right there," said Peter Sam, not quite understanding, "is that why you came all the way here?"

"No, Stuart," chuckled Duke, "she means the station at Rheneas."

"Exactly, Duke," said Miss Celestia, "Rheneas here is named for the station, which comes from the ancient Sudric language meaning 'divided waterfall'."

"Makes more sense," said Duncan.

"I could take you there," offered Peter Sam.

"That's very kind of you to offer, Peter Sam," said Miss Celestia. And with that, she climbed into the little green engine's cab and Peter Sam set off.

As they made their way closer to the station near the waterfall, Peter Sam ground to a halt. He was so eager to help Miss Celestia that he had forgotten to take on more coal.

"Oh, bother!" he groaned, "I'm very sorry, Miss Celestia."

"Don't worry about it," she said while the driver went to phone for help, "you've saved me a ton of walking already. Looks like I'll need to carry on by foot."

And so she continued her journey on foot, leaving behind Peter Sam, who still felt guilty.

"I hope she'll be alright," Peter Sam murmured.

After what seemed like an hour, Miss Celestia looked around to see where she was.

"Where's the waterfall?" she pondered, "Isn't it where I'm supposed to be…?"

Miss Celestia decided to try and sparkle herself there, but when she sounded her whistle, nothing happened. She tried again; still nothing. Out of disappointment, she sat down on a nearby boulder.

"Now my gold dust really is all gone," she realized, "and if I can't find the source for making more, I know how bad the consequences will be. I saw them in my dream last night."

With that knowledge, Miss Celestia stood up once again and made her way through another thick bush when she finally arrived at the waterfall. Unfortunately, she was at the bottom instead of the top.

"Ugh… I have to get to the top, and that's what I've been told," she decided, and began to climb, "the family said I'd find the clue to the source of my gold dust at the top of Rheneas. Why did they stop at the clue? Why not just tell me the source and be done with it? I'm the wrong age for… Ah!"

Without any warning, Miss Celestia had lost her grip, but despite the setback, she kept climbing until finally, she reached the top.

"Thank goodness," she sighed, "I think I see something in that crevice." Slowly, she reached her hand in and grasped hold of a piece of paper. She unfurled it and read it out loud.

"Stoke up the Magic in the Mountain and the Lady will smile… Then watch the Swirls that spin so Well…"

But before Miss Celestia could see if there was more than that, she slipped.

"Woah!"

She fell down the waterfall with a splash! Fortunately, Miss Celestia was unhurt, but she was very wet when she crawled out.

"Well, that was not an enjoyable experience," she said. She looked to make sure she still had the clue, but gasped when she saw it was gone.

"Oh, drat!" she groaned, slapping a hand to her forehead, "I've run out of gold dust and lost the clue to the secret of the source…"

Miss Celestia struggled to remember the clue. "Mountain… smile… what else? Curls… tin… no, that's not right… Ohh! If only there were someone else who had gold dust too…"

Suddenly, she had an idea.

"I have to make a phone call," she said, standing up.