Bill and Ben love playing tricks on other engines, especially Derek and Timothy, because Derek can be a bit vulnerable while Timothy is nearly as gullible as Paxton. One morning, the China Clay Works was very busy, but Edward and BoCo had to take care of passenger duties, so Derek was placed at the Works.

"Now I don't want any tricks," he said as he pulled to them.

Bill and Ben giggled.

"Oh of course, Derek," said Ben.

"No tricks from us!" smirked Bill.

Derek eyed the twins suspiciously and oiled over to Timothy.

"I'd be careful around them," worried Timothy, "Last night they pushed me under the hopper and said I was sleeppuffing last night."

Derek chuckled.

"It's alright, I know them fairly well now."

"Lets hope so," thought Timothy as the engines set to work.

Derek worked hard all morning, bringing trucks down to the harbour and back. But Bill and Ben were being their typical cheeky selves.

"Hey Timothy, think fast!" and Ben bumped the trucks into him.

"Hey!" cried Timothy.

Bill and Ben laughed.

"Sorry... not!" said Ben.

Derek arrived with some empty trucks.

"That's enough you two. We don't need you two getting into trouble," he said sternly.

Timothy gratefully glanced at Derek as Bill and Ben puffed away. They were very annoyed.

"Who's he to stick his radiator where it doesn't belong?" sulked Ben.

Bill snickered.

"Well... if we can't have fun with Timothy, let's have fun with Derek."

The twins giggled as they started to make up a plan.

By the time noon came, Bill and Ben knew what to do.

"He still has teething troubles," Bill said, "so I suggest we get him to pull a long train to the Docks! He won't be able to pull and he'll get stuck!"

"Brilliant!" giggled Ben.

In the main area of the China Clay Works, Timothy had three lines of trucks, one for Bill, one for Ben, and one for Derek.

"Alright Bill, pretend you are ill so Derek can take your trucks," whispered Ben.

Bill agreed and started coughing.

"Oh my Bill, are you alright?" asked Timothy worriedly, "You don't look so good."

"I'm ill," Bill wheezed, and tried to make his face grow as red as possible.

Timothy winced.

"Oh dear. The manager must make new arrangements!" And he went off to tell the manager about Bill.

When he came back, the manager had already shifted the timetable.

"Derek, I'm afraid you'll have to take Bill's trucks as well as your own," he said to Derek, "Can you do it?"

Derek gulped; he wasn't sure his engine could take the load, but he didn't want to disappoint him either.

"I suppose so sir. I'll try my hardest."

"Good," said the manager, "Timothy, take Bill to the shed. We'll see to him later."

"Yes sir!"

Bill secretly winked at Ben as he was shunted into the shed.

Derek set off with his heavy train, but no sooner had he left the clay pits when he felt his engine heat up.

"Ugh driver, I'm not feeling well..."

"Come on ol' boy, you have to keep on going."

"I'll try!" promised Derek, but the load was very heavy, and Derek had a hard time pulling. His engine grew hotter still, and his driver began to grow worried.

"We better stop a siding and let your engine cool down a bit."

"Thank you..." wheezed Derek tiredly.

The driver made arrangements with the signalman and Derek's train was diverted onto a long passing siding. Derek was gaining his breath back when he heard a familiar whistle. The diesel groaned as Ben rattled past with his own train.

"Come on, Derek! Get a move on, slowcoach!" Ben teased as he puffed out of sight.

Derek lowered his brow; his determination flared hotter than his engine.

"Come on, driver. Let's get this train to Brendam. We're running late now."

His driver, surprised but impressed, turned on the engine. Derek roared into life and he slowly trundled out of the siding.

It wasn't long, however, when Derek began to feel hot again.

"Oh bother! I can't keep stopping in sidings!"

"We'll just have to make a run for it," said his driver, and he started adding speed. This was the nail in the coffin. As Derek approached the bend that led to the Docks, his engine felt worse than ever.

"We're almost there! We're almost there!" he shouted optimistically, but it was no good. A loud snap made itself heard, and Derek immediately started losing speed.

"No! No! NO!" Derek wailed. Black smoke erupted from his broken down engine. Derek coughed in his own fumes as his driver braked the train.

"I'm sorry, Derek," he said guiltily, "I should have stopped you sooner. I'll call for help at once."

Derek was too busy coughing to reply. He felt utterly miserable.

The call soon reached the Docks. The Dock Manager ran up to BoCo, who was dropping off passengers at the loading dock.

"BoCo, there's an emergency up the line! Derek has broken down!"

BoCo frowned.

"What about my passengers, sir?"

"Edward'll have to collect extra coaches. Now hurry; with Derek blocking the line, no china clay trains can come in or out!"

A shunter hastily uncoupled BoCo from his coaches. The large diesel honked his horn and hurried off to the rescue.

"Poor Derek," he muttered sadly.

It wasn't long before BoCo arrived. BoCo gasped.

"Derek? Why do you have such a long train? I thought you'd be more responsible!"

"I know," sighed Derek, "but desperate times call for desperate measures. Bill was ill so I had to take his train as well..."

BoCo narrowed his eyes.

"Hmm... I have a feeling Bill just pretended to be ill."

Derek was surprised.

"Why on earth would he do that?"

"Possibly to get you into trouble," BoCo murmured gravely as he backed down onto the fellow diesel. Derek was crestfallen.

"I guess I don't know Bill and Ben as well as I thought..." Derek mumbled sadly as BoCo took him and his train to Brendam Docks.

BoCo's suspicions proved to be correct. The Clay Pits manager had ordered an inspection of Bill, only for the workmen to return very cross.

"This was a complete waste of time! Absolutely nothing is wrong with that engine!" an inspector huffed, pointing a stern finger at a nervous Bill.

"But that can't be right. Bill was coughing and wheezing!" Timothy protested, hoping against hope that Bill was being genuine.

"All just an act, I assume..." grumbled the inspector, "Come on lads."

The manager gaped at the exiting inspectors before glaring at Bill.

"Bill, explain yourself..." he said icily, putting his hands on his hips. Bill smiled sheepishly and attempted to improvise.

"I... um... was ill sir but er... now I feel better!"

The manager glared.

"What a load of rubbish! I should've known you were playing sick! Were you trying to get out of work?" he asked sternly.

Bill gulped.

"O-Oh, uh..."

"No, sir, we just wanted to pay Derek back for being a bossy buffers," said Ben hastily, "Bill faked being ill so Derek would have to take both trains!"

Bill gasped.

"Ben!"

"What? It was either me or you."

"You told me to do it!"

"Did not! It was your idea!"

"Did too!"

"Did not!"

"Did too!"

"ENOUGH!"

Bill and Ben flinched. Their manager turned around to face a shocked Timothy.

"Timothy, do you think you can handle the work alone for a little while?"

Timothy glared at the twins before grinning.

"Yes, sir. With pleasure."

"Good, because I'm going to shut Bill and Ben up in the shed until I decide what to do with them."

"What?!" shouted them together.

"W-We're your task force! Timothy can't do anything on his own!" protested Ben.

The manager didn't stick around to listen as he walked back to his office. The twins' fires were put out and everyone gave them dirty looks as they went about their work. Bill and Ben grew very upset.

BoCo had taken Derek and the china clay to the docks. Cranky looked down at them with a glare.

"The ship was nearly late! What have I told you engines about respecting ships?"

BoCo rolled his eyes as Derek's cheeks flushed with embarrassment.

"It wasn't Derek's fault, Cranky. Leave him be."

Cranky snorted and went back to his loading. Salty cast a sympathetic look at Derek.

"Argh, never mind matey. Soon ye'll be repaired and back in working order again!"

"I know that Salty, but to have that happen I have to be taken to the Dieselworks. Can you take me, BoCo?"

"I'm sorry, Derek, but I have more passengers to deliver, as does Edward," apologized BoCo, "I'm sure someone will be along in due time though."

BoCo honked his horn and hurried back for his empty coaches. Derek was left on the keyside, stranded but not alone. Engines passed through the dockyard, whistling "Hello!" to him but doing little to resolve the situation.

"How long am I going to be here?" Derek wondered aloud, "At this rate, I'll be stuck here forever!"

"Join the club," huffed Cranky.

Just then, a diesel horn blasted. Cranky groaned as Dennis the Lazy Diesel slowly rolled into the dockside with some empty flatbeds, complaining as usual.

"Botheration, these are too heavy! Just moving alone makes my coupling strain!"

"What do you want Dennis? The faster we get you loaded the faster you leave," Cranky grumbled.

"Diesel engine parts," Dennis muttered, "Why couldn't Den or Dart do this job? They're the ones who deal with maintenance, not me."

Derek's face brightened up.

"Did you just say the Dieselworks?"

Dennis raised an eyebrow.

"Yes... why do you ask?"

"Because I'm bound for that way myself! Can I tag along on the front of your train?"

To Derek's dismay, Dennis gaped with indignation.

"You?! Tag alone with me?! Do you know how heavy engine parts are? Adding you onto the load will surely tear me apart!"

Derek sighed, and was about to admit defeat when Salty rolled alongside.

"Argh, I think that's a grand idea, and I'm sure the Dock Manager will agree!"

Dennis lowered his eyelids.

"...please don't."

But indeed he did.

"What a clever engine you are, Derek! Salty, can you please shunt Derek in front of Dennis please? it's apparent he isn't willing to contribute."

"Of course I'm not! I have rights you know!" Dennis seethed.

"You also have the right to remain silent," huffed Cranky.

Dennis spluttered before subsiding to grumbling.

"Argh, in no time, cap'n," grinned Salty. He pushed Derek onto the front of Dennis before scampering off to do more shunting. Dennis scowled.

"Come on, Dennis. You're blocking the line," smirked Cranky. Dennis gave him a glare before slowly rolling out of the dock.

Derek and Dennis scurried up the Brendam Branch Line, but Dennis' laziness was quick to bite him. He was travelling at an incredibly slow rate, which meant he didn't get a good run at Gordon's Hill.

"We're going to get stuck!" gasped Derek.

Dennis grunted.

"You'd think you'd be used to that by now," he muttered, but he muttered it to himself. Derek proved to be right as the train came to a standstill in the middle of the hill. Dennis glared back, seething.

"I'm not moving another inch!" he huffed.

"But you have to! You have a train of engine parts and a broken down diesel!" protested his driver.

"That's exactly why I won't move. The hill was too steep for my tender engine. Now I've broken down. Get that blue one to push us up."

Dennis' driver climbed down from the cab and reluctantly went back to Wellsworth. When he back, he looked red in the face, both from climbing the steep hill and being cross.

"Dennis, Edward is taking too many trains to help us!"

Dennis smirked.

"Then I suppose we can't go any further, can we?"

His driver scowled at him before jogging back down the hill to the station to telephone for aid.

At Wellsworth, BoCo was resting in the yard when the call came.

"Apparently Dennis refuses to move with Derek," sighed BoCo's driver, "We'll have to go and help."

BoCo was cross.

"How many times are engines going to fake breakdowns?" he spluttered, but he soon went up the hill to give Derek and Dennis a push. Dennis was exaggeratedly coughing. No matter how many times Dennis' turned on his engine, it wouldn't budge.

"Come on, move!"

Dennis just rolled his eyes.

"Dennis, do you have any shame?"

Dennis yawned.

"No, not really."

BoCo scoffed.

"Figures..."

BoCo bumped the brakevan and pushed Derek and Dennis, as well as the machine parts to the Dieselworks.

At the Dieselworks, Den and Dart were waiting anxiously for their delivery.

"What's taking Dennis so long?" wondered Den worriedly.

"It's Dennis, he's probably trying to manipulate someone else into doing his work," grunted Dart.

Just then, BoCo's horn sounded out. To Den and Dart's surprise, the strange train rolled into the yard. A sheepish Derek at the front, a smirking Dennis behind him, and finally, an exhausted BoCo at the back. Den raised an eyebrow.

"BoCo? Derek? What's going on?"

"Derek broke down taking too long of a train, but no-one could take him here except Dennis, but he got too lazy do to that so he pretended to break down back at Gordon's Hill, so I was forced to come and take the train the rest of the way," grumbled BoCo.

Den and Dart shared a look.

"...oh."

"I'm truly sorry about this, BoCo. It seems like misfortune is my shadow," said Derek apologetically.

BoCo smiled.

"Never mind, Derek. It was the selfishness of some other engines that caused this predicament, not you."

Dennis whistled innocently, but gasped when he saw the Dieselworks manager storming up to him. The lazy diesel's face paled.

"Dennis, I expected better of you. I will notify The Fat Controller of your utter idiocy," the manager said sternly, "Your laziness is too much to bear at the moment." His face softened as he turned to BoCo. "BoCo, bring Derek and the machinery in so we can have him repaired."

"Yes sir," said BoCo, casting a smirk at a sullen Dennis as he passed.

That evening, at the China Clay Pits, Bill and Ben were let out of the shed, only to be sternly lectured by the other engines. The twins each raised an eyebrow at each other.

"Derek is a responsible and hard-working engine, and he didn't deserve such cruel treatment from you two," scolded BoCo.

"He thought you two were his friends," added Timothy sadly.

Ben blinked.

"Wait, we were his friends?"

BoCo scowled.

"How can you two feel not any remorse for this? He broke down for goodness' sake!"

"It's not our fault he wasn't repaired properly," protested Ben.

"Besides, it was only a harmless joke," added Bill.

"He's at the Dieselworks, I'd hardly call that harmless," huffed BoCo.

"Whatever, it's not like we'll miss him," grumbled Bill.

"Yeah, he's just a nuisance if anything," agreed Ben loftily.

Marion rolled her eyes, and puffed up to Bill and Ben, pointing her shovel at them.

"You don't realize what this means for you, do you?"

Bill and Ben glanced at each other.

"Uh... no?"

"It means that with Derek down, we have to work harder than ever to meet our quota," explained Marion hoarsely, "which means you will have to do most of the work."

Bill and Ben stared at Marion, slack-jawed. BoCo smirked.

"You two will miss him in due time I suppose."

Bill and Ben glanced at each other and gulped. But that's another story...