The summer season on Sodor was arriving and the narrow gauge engines were tired out.

"It's not fair!" complained Duncan, "Why are we always overworked in these months?"

"Because there's plenty of passengers," pointed out Freddie.

"And goods," panted Luke, "The Blue Mountain Quarry is busier than ever! Owen and Merrick are so tired out that I fear they'll break down."

"Even I think there's too much to do," admitted Peter Sam, "Especially with maintenance."

Rusty sighed.

"I know... I have to mend the line practically every day thanks to Duncan derailing all the time."

"Hey!"

"Well, you do!"

"It's true," said Skarloey, "I suppose there is a bit too much to do, but I believe we can manage."

"Oh please," scoffed Duncan, "There's way too much to do and you know it!"

"Silence!" shouted the Thin Controller and a Diesel horn sounded in the distance.

"That's not like any horn I ever heard, and I know horns," said Rusty quietly.

Just then a black Welsh Highland Railway Diesel oiled into the yard.

"Well, this looks... interesting," he muttered rudely, "Why are you all mostly steam?"

"Shut it," muttered Sir Handel.

"Why?" asked Paul angrily, "I can have an opinion."

"But first you need a justifiable argument." said Peter Sam.

That shut Paul up.

The Thin Controller climbed down from the Diesel's cab. "Everyone, this is Paul."

"Paul?" asked Bertram.

He then grinned.

"Well, let's all jump in to give this newcomer some hospitality. Everybody, sing! Welcome Pauuuuul, we're happy to have you hereeeee-"

"Oh, shut up." growled Duke.

"Okay... I guess you hate singing. Let's do some poetry instead then. Paul is a Diesel, just like Rusty. My oh my, he is quite feisty-"

"NO!" cried the engines.

"Fine..."

"Anyway... Rusty, you'll show Paul around," said the Thin Controller.

"Why me?" spluttered Rusty.

"You're the only engine available Rusty. Fred can take care of your maintenance."

"Yes sir..." sighed Rusty.

The Thin Controller nodded and went to get his trusty bike from the bike rack by his house.

"Why does he hate cars anyway?" asked Mighty.

"I think it's because of pollution or something stupid," muttered Duncan.

"So... this railway of yours. Is it all full of steam kettles like you?" mumbled Paul.

The engines were appalled.

"We're very useful!" spluttered Rheneas, "Many of us are over a century old!"

"Exactly. You belong in museums or a heritage railway." said Paul indignantly.

"We're Really Useful Engines, You'll see." fumed Mac.

"Whatever... Come along, Crusty, or whatever your name is."

"Rusty..."

"Yeah, that's it. Let's go see how 'good' this railway supposedly is."

Rusty was fuming as he and Paul scurried down the line.

Rusty and Paul arrived at Cros-ny-Cuirm.

Paul looked around, unimpressed.

"This station looks dirty! Must be from all the soot."

Rusty scowled.

"Come on, lets just go to the Blue Mountain Quarry..."

Paul became excited.

'Finally, a quarry!"

Rusty rolled his eyes and set off towards Skarloey Station.

"...oh no."

At the Blue Mountain Quarry, Luke and Ivo Hugh were pushing and pulling trucks to where they needed to be.

"So much work to be done!" cried Ivo Hugh.

"I suppose it's not so bad once you get used to it." chuffed Luke.

"Oh look, there's the new Diesel! Thank goodness you're here," panted Ivo Hugh.

Paul snorted and started the trek up to the upper terrace, not having a clue what he was doing.

"What the? You're not supposed to be there!" cried Luke, but Paul ignored him.

He scurried up the hill and noticed some trucks.

"I know..." he said to himself.

Paul shunted some trucks onto Owen, too fast and too hard.

"On! On!" cried the trucks.

"Uh, what's going on?" cried Owen, "Something doesn't feel right..."

The trucks flew down Owen and smashed to pieces at the bottom.

"Oh dear..." said Owen.

"Owen, are you alright?" cried Paxton.

"I'm fine... I guess.." said Owen.

Rusty was furious.

"You caused a serious accident, and now the Blue Mountain Quarry won't be able to supply slate until Owen is repaired," he scolded Paul, but Paul was so stubborn he didn't hear what Rusty had said.

Paul went backwards over Blondin Bridge and was now at Merrick.

The gantry crane was snoring loudly, as usual.

"Wake up idiot!" cried Paul and honked his horn.

Merrick woke up with a start.

"Ah, what's going on?"

He looked down to see a scowling black Diesel.

"Oh, is that you Fred?"

"I'm not 'Fred', I'm Paul, and you're sleeping on the job."

"Does he always act like this?" Paxton asked Rusty.

"Afraid so," replied Rusty, "He acts like those stubborn Diesels I hear about on the North Western Railway."

"He acts worse in my opinion; he's very rude indeed," said Paxton.

"I know..." said Rusty quietly, "Come Paul, we've got to go."

"Seriously? I was just getting warmed up." grumbled Paul.

"Warmed up with what?" asked Luke.

"Warming up with trash talk. It works wonders you know. Like... 'Wake up, you idiot.'"

"Right..."

Suddenly Rheneas puffed in with a long train of empties.

"Bubbling boilers! What happened!?"

"Paul knocked some trucks down Owen and now he needs to be repaired," replied Rusty gravely.

"I hate to see how he'll handle passengers..." sighed Rheneas.

Paul laughed and raced out of the quarry.

"Bother, now I have to go chase him," scowled Rusty and he raced after Paul.

"Good luck with that." murmured Owen.

"Get back here you imbecile!"

"Can't catch me!" grinned Paul.

Paul raced on the bridge by the Peel Godred Branch Line and finally stopped at Ulfstead Castle.

"Wow... this is the first tourist attraction to look impressive!"

Rusty finally caught up with Paul, but was panting constantly.

"Don't you do dare do any damage to it," he cried, "We just finished building it a couple of years ago."

"Relax, I won't do anything... Oh look, another steam kettle."

It turned out to be Stephen, and he took a bit of offence to Paul.

"Watch your mouth youngster. Who is this rascal anyway Rusty?"

"He's the new engine. I recommend just ignoring him." said Rusty, rolling his eyes.

"Alright then. I suppose he won't cause too much trouble, right?"

Suddenly, they heard a smash!

Rusty hurried to see what was the matter.

He gasped when he saw what happened.

"Oh no, Millie!"

"Ce qui s'est passé!?" cried Millie.

"Uh... is that Portuguese?" said Paul, confused.

"That's French you idiot," scolded Rusty, "What were you thinking?!"

"He wasn't, clearly," chuckled Stephen.

"I was just chuffing along to get something for the groundskeeper and then this Diesel comes in and crashes into me like he doesn't even care!" shrieked Millie furiously, "Now I have to be repaired!"

Paul frowned.

"Well, it's your fault."

"How is it my fault?" cried Millie.

"Because you're blue."

"That doesn't even make any sense!"

"You don't make sense." muttered Paul.

"What is going on?" asked the Earl, who had heard the commotion, "Oh no, Millie! What happened Rusty?"

"This new Diesel crashed into her. Don't ask how, he just wasn't paying attention."

"Figures... I'll have to phone the Thin Controller. We'll have you back on the rails in no time Millie." and the Earl telephoned the Thin Controller.

"Mr. Percival. One of your crazy Diesels smashed into my private engine! I like a good surprise and all, but it must be a positive surprise!" cried the Earl.

"I'll be there right away," replied the Thin Controller, and he hung up.

He looked around for an engine.

"Duke, can you give me a lift?"

"Of course sir," grinned Duke, "Let's go!"

And the Thin Controller boarded him.

Soon, they soon arrived at the castle.

Suddenly Connor arrived at castle to drop off some passengers.

"What in the blazes happened?" he asked.

"That's exactly what I intend to find out," said the Thin Controller.

He walked towards Paul.

"I heard about your intentional accidents at the Blue Mountain Quarry, and I must say that I was less than impressed, but now you've gone all the way to crash into Millie!"

Paul gulped.

"Sorry sir..."

"You better be too, because I have to pay for all the damages you caused."

Rusty couldn't help smirking at Paul.

Paul glared at the little Diesel.

"I'll get the Breakdown Train." offered Rusty.

"Good," said the Thin Controller, "We'll need it for this situation."

Paul just sulked.

When Rusty got back, the crane put Paul and Millie back on the rails, and soon, Paul was back at Crovan's Gate for repairs, since the Skarloey Railway didn't have a line going to the Dieselworks.

"I hope you learn to be Really Useful Engine," scolded Victor, "or else you'll be sent back to your old line."

Paul knew Victor was right.

"I'm sorry, Spanish engine."

"I'm actually Cuban..."

"Oh."

Just then, Rusty oiled in.

"How is Paul, Victor?" he asked.

"He's in a siding with the workmen. You can go see him for a minute. I don't know why you'd want to, after all the chaos he caused, but by all means, you can go."

"Thanks Victor," smiled Rusty and he went over Paul.

"Rusty, I'm sorry. About everything. I was a Really Useless Engine... I, uh, kept getting identities wrong."

"It's alright; newcomers are often like you. Soon you'll learn." said Rusty, "But do make the learning quick. The Thin Controller's going to keep a watchful eye on you from now on."

And Rusty oiled away.

Unfortunately for Rusty, he didn't see a sly grin on Paul's face.