Steam engines from different parts of the world run on many different types of coal.

For example, American engines like Hank and Porter run on different coal than Sudrian engines like Thomas and Percy.

That's one of the reasons American engines have to be rebuilt when they come to Sodor; their fireboxes won't support Sudrian coal.

One day, coal was being loaded into some trucks at the Docks.

Cranky was lowering sacks of it, grumbling and complaining all the way.

"All this coal is going to make my face sooty!"

"Why isn't there gold coal? I want that!"

"Stupid coal..."

"He never stops, does he?" murmured Porter as he shunted the trucks onto a siding.

Next to the siding were two other lines of coal trucks.

One line was meant to be taken back to the Mainland due to a shipping error, while the other two would stay on the island.

Billy arrived to take one line of trucks to the coal bunkers on Sodor.

"Hello Porter," said Billy happily.

Porter looked up and smiled.

"Hello there Billy. What's up?"

"Nothing much, just delivering these coal trucks." Billy explained.

"Oh, so you're the engine meant to do the job. I wish you the best of luck, Billy."

"I can do the job, thank you," Billy huffed.

The shunter coupled him up to the line of trucks on the far left.

Salty shunted the brakevan.

"I meant no offense, Billy," stuttered Porter, but Billy was already setting off on his journey.

Billy traveled all over the railway, giving coal to all the engines.

"Aye, thank ye Billy," said Douglas sincerely at Callan.

"Thanks, Billy! We really did need this coal!" Rosie grinned cheerily at Knapford Yards.

"This'll be perfect for my next fish delivery," said Arthur at Norramby.

Soon, almost all the steam engines on the island had been given the new coal.

Billy felt quite proud of himself as he rushed into Ffarquhar, to give Thomas the new coal.

Thomas was pleased as Billy braked alongside him.

"I was just running low on my supply," the blue tank engine voiced, "What nice timing!"

"I'll say," Billy yawned, "Now if you excuse me... I need some sleep. I must've worked myself too much."

"By all means, rest in the shed," said Thomas.

"Thanks..." Billy said wearily as he backed into the shed.

The fireman started shoveling the new coal into Thomas' firebox, and soon, his fire was blazing nicely.

"Very nice..."

An hour or two later, Billy was still dozing when suddenly he heard loud wheezing.

He opened his eyes, annoyed.

"What's making that racket?" he spluttered.

The wheezing sound came again.

To Billy's shock, he saw that it was Thomas, struggling to pull his coaches out of the station.

His cheeks were red and his funnel was pouring black smoke.

"Thomas, we're not that heavy," snorted Annie indignantly.

"Much too slow," agreed Clarabel.

"I... can't... pull..." Thomas wheezed.

"Something must be wrong with the coal. I'll phone for Toby." said the driver and he phoned the yardmaster.

"Thomas' coal isn't burning right. We need Toby to come and pick up the passengers."

The yardmaster, who was at Elsbridge, looked from the phone to Toby, who was groaning in the shed.

"There, there, Toby," consoled Henrietta, "You'll feel better soon."

"We're sure of it," said Victoria.

"Ohh... I hope so..." the tram engine moaned.

"Sorry," replied the yardmaster, "But Toby doesn't feel well either. Try Daisy, since she's a Diesel."

As soon as Daisy was told the news, she wasn't impressed.

"Huh! So Thomas broke down, eh? Hmph! Typical!"

"Not exactly, Daisy," said her driver as he started her up, "Some bad coal seems to have surfaced, and Thomas got infected with it."

Daisy frowned.

"Oh... Oh my... That does sound painful..."

"It is," said the driver grimly as the railcar set off for Ffarquhar.

Later, Daisy arrived to take Annie and Clarabel.

She was in a more sympathetic mood, now that she knew what exactly was causing Thomas to be out of commission, but she wasn't exactly cheerful.

Daisy just rolled her eyes.

Billy shunted Thomas onto a siding out of the way.

"What happened Thomas?" asked Billy.

"I... don't... know..." wheezed Thomas and he coughed before he could think of anything else.

Billy was worried as he turned to Daisy.

"Do you know, Daisy?" asked the orange tank engine.

"I'm... not sure." said Daisy worriedly, "I do hope you feel better, Thomas."

Daisy purred away with the coaches, still grumbling under her breath.

"I wonder if other engines are infected," Billy said to himself as he puffed away.

Unfortunately, Billy's assumption was completely correct, because some more engines could be seen at Tidmouth Sheds as Billy passed them.

Oliver's face was as green as his paintwork, while Arthur didn't look too well either.

BoCo's horn blasted as he backed down onto Oliver.

"What are you doing here, BoCo?" asked Arthur hastily before coughing.

"I'm here to take you two to the Steamworks, to check what exactly is wrong with you."

BoCo was coupled up to Oliver, and then to Arthur.

He looked back at the two tank engines.

"We're ready to go!"

"...okay, BoCo." moaned Oliver.

Oliver's wheezing alarmed BoCo, and he wanted to make sure they were alright.

"You will be okay, right?" asked BoCo.

Arthur and Oliver said nothing, but did wheeze and cough.

BoCo cringed.

"Oh my, this isn't good at all," thought Billy as he cringed himself, "I must tell the Fat Controller at once!"

At Knapford Station, the Fat Controller was looking worriedly at his schedule, thinking of how to rearrange it when Billy puffed in.

"Sir, sir! I think something's wrong with the coal! I saw Arthur, Oliver and Thomas with black smoke, and they were wheezing and coughing. There are probably more engines with it too!" cried Billy.

The Fat Controller was horrified.

"Oh no, this could be detrimental! We must get a coal inspector, and the nearest engine with the bad coal, so we can identify what we're dealing with here."

"Yes sir," said Billy urgently as the Fat Controller climbed into his cab.

Billy puffed quickly to Tidmouth, where they phoned for a coal inspector.

"Get here as soon as you can!"

"I'll be right over."

The inspector swiftly arrived by bus, and raced up the stout gentleman, and orange tank engine.

"What seems to be the problem?"

"We need to inspect some coal," explained the Fat Controller, "I believe we have... a difficult situation."

Billy looked over to find Sidney, who was shunting some oil tankers.

"Excuse me, Sidney?"

"Yes?" asked the jovial diesel.

"Who's the nearest steam engine?"

"Oh, uh... Let me think... Um... I believe Falcon or... whatever his name is at Arlesburgh Junction," said Sidney.

"I assume you mean Duck, right...?"

"Oh yeah, that's his name!"

"Right! Let's go!" Billy cried as he set off for Arlesburgh Junction, with the Fat Controller and the coal inspector in his cab.

At the junction, Duck was moaning to Jock as he wheezed.

"Oh dear, oh dear... I don't feel well." mumbled the Pannier tank in despair.

Jock snorted, getting quite tired of Duck's rambling.

"Maybe you ate a duck by accident, who knows."

Billy puffed in with the people still in his cab.

"Billy? What's going on?" Duck asked weakly.

"We're having an investigation, Duck," the Fat Controller explained, "This coal inspector here's going to identify your coal so we can eradicate it."

The coal inspector walked out of Billy's cab and examined the coal in Duck's bunker.

He frowned.

"Oh dear..."

"What?" asked Duck's fireman.

"Apparently you've all been using Bituminous coal." said the coal inspector.

"I'm guessing that's bad..." said Duck meekly.

"Hmm, indeed," continued the coal inspector, "Your fireboxes cannot support this type of coal. Because of this, we have engines feeling sick. Unfortunately, it's a lot of them."

The Fat Controller was worried.

"But that means the Diesels will have to do all the work! They'll be lazy for sure..."

"Not all diesels are bad, sir," said Duck's driver, "There are some that are sensible like BoCo and Paxton. We should be alright."

"Maybe, but some are more difficult to handle."

The Fat Controller sighed and walked back to Billy's cab, wondering what to do.

"Sir, will we have to close down the railway?" Duck asked worriedly.

"I doubt it, but if it gets serious enough, we may have to shut down services until we can get the new coal. We can't risk damaging my engines, after all."

Unfortunately, that wasn't the end of it.

All over the island the coal was making the engines sick.

At the Clay Pits, Bill and Ben had just had their fireboxes cleaned and were resting in their shed, waiting for the new coal.

Luckily, Timothy was an oil-burning tank engine, and could handle the work, but he quickly grew tired.

"I'm not sure how long I can handle all of this. I hope that new coal arrives soon. If this keeps up, my wheels will fall off!"

Bill looked to Ben with a frown, realizing Timothy had a point.

Donald was wheezing when he was with Duck at Arlesburgh Station.

"Och, this is th' wirst coal a've ever hud," said Donald.

"I agree. This isn't Great Western coal at all, said Duck.

"Ah dinnae cop weel either. A'm feelin' lik' mah tender wull fall apairt!" moaned Douglas.

Murdoch was one of the few engines who wasn't infected with the coal.

Because of this, the Fat Controller sent him to Brendam to collect the other two lines of trucks, so they could restore order.

Salty and Porter were there, shunting and biffing.

Porter was pleased as Murdoch backed down onto the long line of trucks.

"Thanks Murdoch!" called Porter, "You really are a savior!"

The American tank engine whistled with delight.

"Argh, I've got to agree with that, me heartie. Who knows how much longer this would've lasted if it weren't for you," added Salty.

"No problem. Luckily I didn't need any coal in my tender." replied Murdoch and he puffed away with his long train.

At Tidmouth, more engines were coughing and sneezing.

Thomas had just had his firebox cleaned out, so he felt fine now.

He waited for Murdoch to arrive with the English coal, so he could get back to work.

All the same, he detected a sense of curiosity within him about the whole event.

"I wonder how this happened," he said to Edward.

"I'm not sure I have any answers. This could be an accident," murmured Edward, before coughing.

Before Thomas could reply, Murdoch puffed in with the coal.

"Hello everyone. Here's the coal!" called Murdoch.

Thomas was pleased as his fireman shoveled the clean coal into his firebox.

This time, his fire burned brightly as the coal started to burn.

Edward, after a fit of coughing, finally spoke up again.

"On the other hand, it... *cough* could've been on purpose."

Thomas frowned and puffed out of the shed; he had a lot to think about.

Emily was particularly cross about the situation.

"I'd like to figure out who did this! They must- *cough* Oh, I'm so sore..."

"We all are. *cough* I'd *cough* stow it if *cough* I were *cough* you," sniffed Henry.

Edward was alarmed at Henry's condition.

"Henry! You sound awful!"

"I'm the worst of the lot..." replied Henry, "It might be a coincidence, or... Achoo!"

Soot covered himself, as well as Edward and Emily.

"Sorry... I was going to say it could also be my prone to illness.

"You should be the next to get your firebox cleaned out!" Edward said, "The rest of us can wait... *cough*."

"But somebody has to find out who was responsible for all this!" interrupted Duck, "Whether it was an accident or not!"

"It could've been Diesel 10 if he somehow sabotaged coal." said Emily.

"But how can a Diesel make coal unusable?" wondered Duck.

"Maybe he poisoned *cough* it with some sort of *cough* chemical," suggested Henry.

"Or maybe he used his claw to crunch it up, put it somewhere, and then sprayed it with the chemical." chuckled Duck.

The engines all shared their idea on the matter, but nothing seemed that realistic.

"I think it's best we don't assume someone like Diesel 10 did it," Edward wheezed, "After all, he'd be easily caught and his schemes are often arbitrary anyway."

Meanwhile, before returning to his branch line, Thomas decided he had to figure out who was responsible.

"I have to know who did this. This is an important matter that we must solve quickly. We'll find out who made us sick whether it be Diesel...or steam."

An idea suddenly dawned upon him.

"I know! I'll go to Brendam! Perhaps I can check the schedule and figure out what happened. That's it!"

Thomas stormed to Brendam Docks, as quickly as his wheels could carry him.

At the Docks, Billy was shunting some trucks alongside Porter when Thomas arrived.

"Hello Thomas!" called Billy as Thomas pulled up.

"Hi Billy, Porter." said Thomas, "Hey Porter, can I ask you something?"

"Of course!"

"Can you tell me when the coal first came here?"

"Around 2:00 yesterday," replied Porter.

"Hmm... And who delivered the trucks to all the coal bunkers?"

Porter gulped, not sure what to do; he didn't want to betray Billy, yet he didn't want to betray Thomas either.

"Um..."

He looked at Billy, then back to Thomas.

"Erm..."

Thomas squinted his eyes.

"It's clear you know, Porter. Come on, spit it out!"

Porter admitted defeat as he cast a sympathetic look at Billy.

"Billy delivered the trucks..."

Billy's eyes widened in alarm.

"What?! I didn't know! I swear!"

Thomas was cross.

"Billy! I might've known that you would be behind this. Was it your carelessness or did you do it on purpose?"

"You have to believe me Thomas, I swear! I didn't do anything!" Billy defended himself.

"Huh! We'll see what the rest of us have to say about that!"

Thomas raced away, as Cranky sneered.

"Hmm... I like drama."

Porter groaned, realizing the mistake he made.

"Uh oh... Sorry Billy... I didn't want to get you into trouble... I just... I just had to be honest about the whole thing."

Billy was upset about the ordeal, yet he decided it would be best to not snap at Porter about it.

"It wasn't your fault Porter... But I just hope I don't get into too much trouble."

"Doubt it," smirked Cranky.

James and Percy arrived at Tidmouth Sheds together to find Thomas telling the other engines about the Docks' records.

"So Porter told me that Billy had delivered the trucks!" Thomas told the engines, "He must've done it on purpose to make us all sick, so he could do all of our work to prove how amazing he is!"

"So apparently Billy's responsible!" spluttered Gordon, "Disgraceful!"

"Disgusting!" put in James.

"Despicable! *cough*" finished Henry.

"But why would Billy do such a thing?" questioned Percy.

"Quite right," agreed Emily, "It doesn't make sense."

A horn interrupted the conversation as Bulgy drove by on the road with Emily's normal passengers.

Thomas, noticing the bus, suddenly got an idea.

"Bulgy!"

Bulgy braked, immediately annoyed.

"What do you want?" he asked rudely.

"Can you go to the station and tell the Fat Controller about Billy?"

"What did he do?" asked Bulgy.

"He gave us all the bad coal to make us sick!" cried Thomas, before anyone could stop him.

"Sure, I'll go report 'im. Justice is mine, heh heh."

Bulgy drove away, but Edward wasn't convinced.

"Thomas, don't accuse others for something. Billy isn't that bad of an engine."

"He's right," agreed Toby, "He may be careless but-"

Thomas had already chuffed away to his branch line before Toby could finish.

"Well, we'll have to find the Fat Controller before Bulgy does..." said Toby.

Before anyone could say anything, BoCo arrived to collect Henry.

"Come on Henry, time to get your firebox cleaned," he said.

"Oh, thank you BoCo." Henry said gratefully, "I needed this."

BoCo grinned as he towed the big sick engine away.

"There goes one candidate." grumped Toby flatly.

Emily looked to Edward and Toby.

"Both of you are old and not that fast. Or at least right now. *wheeze* Perhaps somebody else should go."

Everybody looked to Gordon.

"Me?! No way! Besides, I just got my firebox cleaned out. No way I'm going to waste my coal on some bus. Besides, Billy's guilty anyway. It all makes sense to me."

"Gordon, you're the fastest engine on the railway!" pleaded Percy.

"No I'm not, Pip and Emma are! Ask them!" snorted Gordon.

Percy got an idea to try and get Gordon to go.

"Perhaps this could be your chance to prove you're faster...!"

Gordon was cross at Percy for him trying manipulate him.

"That won't work either! I've become friends with Pip and Emma. Don't try your stupid manipulation."

The engines were now desperate.

They looked to Emily when Pip and Emma raced into Tidmouth.

"See, there they are!" cried Gordon.

"Percy, go tell them!" James spluttered.

Percy gulped.

"Do I have to?" he shivered.

"Go on scaredy engine; you know them!" huffed Gordon.

Percy sighed and puffed up to the station.

Emma looked over to the little engine as he braked.

"Hello Percy," said Emma.

"Uh, hi you two. Where are you going?" asked Percy.

"To Barrow, as always." chirped Emma. "Oh, silly me... Can I ask you to get to Knapford before Bulgy?" continued Percy.

Pip and Emma looked confusingly to each other.

"But why?" asked Pip .

"Thomas and some of the others are accusing Billy of the bad coal, but some of us, including me, feel it's unfair. However, Thomas already sent Bulgy to go tell the Fat Controller, so you have to get there first and tell him it was all a misunderstanding."

Pip and Emma knew it was important if Percy talked in such long sentences.

"Right, Percy!" said Emma.

"We're going!" called Pip and they raced away.

"Phew..."

"Come Pip, we have no time to lose!"

Pip and Emma raced along the tracks at high speed.

Bulgy was on the road alongside them, not paying the slightest attention to Pip and Emma; he didn't really know or care what they were doing.

"Hi Bulgy!" said Pip.

"Bye Bulgy!" said Emma as they flew by.

Bulgy was surprised.

"What the heck? Why would you purposely try and pass me? Eh, I don't care anyway..."

"That was easy," giggled Emma.

"Of course it is; we are pretty fast." grinned Pip as they could see Knapford up ahead.

At the station, Diesel 10 was trying to reason with the Fat Controller to scrap steam engines.

"Please sir, if you just got Diesels like me, this wouldn't have happened."

The Fat Controller shook his head.

"I doubt it. Besides, your diesel fuel is just as likely to get poisoned. Enough of you stupid stories, Diesel 10."

Diesel 10 was cross and snapped Pinchy.

"But sir!"

Suddenly Pip and Emma arrived, interrupting the increasingly tense conversation.

"See? Like Pip and Emma; they can replace Gordon!" said Diesel 10.

"Actually they're only covering for him since he's in no shape to pull the express right now." said the Fat Controller.

Diesel 10 growled angrily.

"Hello!" called Pip and they stopped.

"Pip? Emma? Why did you stop here? This isn't your station!" boomed the Fat Controller.

"We're here to deliver a message." said Pip.

The Fat Controller blinked.

"Come again?"

"Thomas sent Bulgy to tell you about Billy, who is currently being accused of delivering the bad coal on purpose." explained Emma.

Suddenly Bulgy drove up on the road.

"Ha, perfect timing! As always... Sir, I've got to-"

The Fat Controller held up his hand, interrupting Bulgy.

"Everyone, be quiet! What in the world is going on here?"

"We just said so, sir..." murmured Emma.

"So Thomas is accusing one of my engines?"

Pip and Emma murmured in unison, "Yes."

The Fat Controller thought for a moment.

"Honestly, I wouldn't blame him."

"What?!" cried Pip, Emma and Bulgy together.

"A mistake any engine could make. Besides, Billy's first day here wasn't the best one," replied the Fat Controller, "and I'll find out who loaded the boat with coal too. I'm not saying he should've accused him, of course."

Bulgy, Pip, Emma, and Diesel 10 were surprised.

"Anyhow, I'll find Thomas soon enough. Winston, let's go."

"Alright, sir." said Winston as the Fat Controller closed the door to his inspection car.

Winston drove away quickly.

Whiff arrived with a train full of rubbish.

"So what's going on?" he asked cheerily.

Nobody responded.

"Why's it so quiet?" asked a puzzled Whiff as the engines left.

"I don't smell that bad, do I?" asked Whiff to himself.

Thomas was with Annie and Clarabel in the carriage shed.

"Well Annie, Clarabel, it seems that Bulgy hasn't come back with the Fat Controller yet," questioned Thomas, "I wonder why?"

Annie and Clarabel were cross with Thomas' decision.

"Thomas! Why would you accuse Billy?" asked Clarabel.

"Well..."

Suddenly the Fat Controller drove up in Winston.

"Thomas! I'd like a word..." said the Fat Controller flatly.

Thomas was surprised that he wasn't with Bulgy but puffed over.

"Yes sir?" the tank engine asked, slightly nervous.

"Thomas, I don't like it when other engines accuse my engines of something they didn't do!"

Thomas was worried.

"Well, I'm sorry sir, but, uh, I didn't know..."

"Billy didn't know either Thomas," said Annie.

"You shouldn't have accused!" scolded Clarabel.

Deep down in his boiler, Thomas knew Annie and Clarabel were right.

"I'm sorry sir..." whispered Thomas.

"I'm not the one you should be apologizing to." said the Fat Controller gravely, "Billy should be along with a train."

Thomas was surprised as Billy puffed in with a flatbed of Diesel fuel, for Mavis.

Thomas sighed as the Fat Controller started to leave.

"Hm, perfect timing."

Billy overheard Thomas and glanced angrily at him.

"Billy..."

Billy scowled at himand looked away.

Thomas tried again.

"Billy... look, I'm sorry. I shouldn't have accused you of anything. You can be careless sometimes, but then again, so was I when I was young. You're still really reliable in your own way. Can you forgive me?"

Billy thought for a moment, and finally realized it would be silly to blame Thomas when, to be fair, it was his mistake.

"I suppose I do, Thomas. It'd be silly to be like I was when I first arrived and call you bossy," the tank engine grinned.

Thomas grinned too and the coaches chuckled at the happy scene.

Now the coal is cleared from the island and the engines are racing along again.

Best of all, Billy and Thomas are friends again.