SEEING IS BELIEVING

Spencer smirked proudly as he made his way down the main line towards the mainland with a Pullman coach in tow. He whistled as the Vicarstown Bridge came into view.

"Private engine coming through!" he grinned, despite no one being around to hear him... or so he thought. Another whistle blew from the distance, but it wasn't one that Spencer recognized. He narrowed his eyes as a large, silver tender engine he had never seen before rumbled onto the bridge.

"Who is that?" Spencer muttered.

"Hello!" the engine called as he raced past with a long train of steel. The steam from his three funnels created a thick cloud that blocked Spencer's vision, and the streamlined engine screeched to a halt.

"I can't see a thing!" Spencer complained loudly, but the engine had already left.

Down the line at Vicarstown, James the Red Engine was picking up some passengers before heading down the line with a local service. He didn't notice an engine slide quietly into another platform, who grinned eagerly at seeing him.

"Why, hello, James!" James jumped in surprise, as his eyes snapped to the other side of thes station. He gasped.

"Merlin?"

"Yes, it is I!" Merlin said dramatically, "You didn't see me there, did you? Don't worry, I get that a lot." James rolled his eyes.

"What are you doing here? I thought you worked at that…" He hesitated as memories of being held captive on the mainland came flooding back to him. "...Steelworks."

"Oh, I do! But steel has to go somewhere once it's made, and Frankie said this delivery here had to go to the Island of Sonar-"

"Sodor," James interrupted, deadpan. Merlin didn't seem to notice.

"-and I wanted to see what it was like for myself, so of course I volunteered! Now, here I am!" Merlin beamed proudly. James wasn't sure what to think. Luckily for him, Merlin kept talking. "Say, Frankie also said something about Brondam Docks. Do you know where that is?" James opened his mouth to correct him but instead sighed.

"Keep going straight until you reach a large junction just past Wellsworth. Go down the branch line, and don't stop until you reach the docks. You can't miss it." Merlin whistled and started rolling out of the station.

"Thank you, James! Pleasure to be working with you!" James cracked a smile as Merlin rolled out of sight.

Merlin carefully followed James' directions, making his way to Brendam Docks. He was so focused that he didn't notice the shocked looks of the engines he passed by. When he reached the docks, he was amazed by all the hustle and bustle.

"What a marvelous harbour this is! If only the others could have seen this," he sighed wistfully.

"Well, thank ye, matey!" chuckled Salty as he rolled alongside, "We do our best here. Isn't that right, Cranky?" Cranky, who had been unloading a ship, turned around.

"Sure," he scoffed, obviously unenthusiastic. He narrowed his eyes at Merlin.

"What kind of engine are you supposed to be?"

"Oh, I didn't introduce myself! I'm Merlin, an experimental engine! I've come from the Mainland!" He grinned.

"I can also turn invisible!" Porter raised an eyebrow as he passed by with some trucks.

"Invisible? How do you manage that?"

"With my three funnels, of course! Watch!" Merlin cleared his throat theatrically. "Invisibility on!" He closed his eyes and a cloud of steam erupted from his three funnels, covering him completely. The cloud eventually dissipated, revealing Merlin to be still there. Salty and Porter shared a look. Merlin opened an eye.

"See? You can't see me, can you? Incredible, isn't it?" Cranky rolled his eyes.

"Well, you're a few bolts loose alright. You'd fit right in here."

"Cranky!" Porter scolded before trying to smile genuinely at Merlin.

"Very… impressive, Merlin!"

"Why, thank you! It's a pity the others at the Steelworks don't appreciate it the way you all do." He gasped excitedly.

"Why don't I stay here, just for a while? I'm sure Frankie won't mind if I'm a little late. Besides, I still need to see Thomas again!"

"So you know Thomas, do you? Well, that explains a lot…" Cranky muttered. Merlin grinned at Salty.

"Any work I can do while I'm here?" Salty glanced at a long goods train on the other side of the quay.

"Well, er… Douglas was supposed to take this lot to Knapford, but he's been delayed, so-"

"On it!" Merlin cut in quickly, hurrying to fetch the train. Salty frowned at Porter.

Soon enough, Merlin was hard at work on the railway, hauling goods trains up and down the main line. He greatly enjoyed the change of scenery from the dark interior of the Steelworks, and was eager to chat with anyone he came across, including showing off his "trick." It wasn't long before the railway was buzzing with talk about Merlin.

"Did you know he can turn invisible, Sidney?" Paxton asked giddily at the shunting yard. Sidney gasped in amazement.

"Invisible? Wow! Uh… who are you talking about?" The two heard a whistle and Percy rolled in, looking just as puzzled as Sidney.

"Yes, Paxton, what are you talking about?"

"A magical engine from the Mainland has come to Sodor, Percy! He can turn himself invisible! I wonder if he can teach me how to do that…" Percy gasped excitedly.

"A magical engine! That sounds very exciting! Where are they?" Paxton thought for a moment.

"Well, uh… I don't know. Think it'd be a bit hard to spot an invisible engine, wouldn't it?" Percy pouted and rolled away, now determined to find the supposed "invisible engine."

However, to Percy's surprise, everywhere he went throughout the day, he never saw the "invisible engine", but he did hear everyone talk about them, much to his growing frustration.

"All he has to do is cover himself in steam and poof! He's gone!" Rebecca chatted excitedly to Emily as Percy rolled through Maron.

"Steam engines can be so odd, Den. Did you know there's an invisible engine roaming around?" Dart asked Den at the Dieselworks.

"Uh… no," Den replied simply.

"It's odd, isn't it? Why, 'e could be 'ere right now!" The two looked over to see Percy rolling in with a delivery of parts.

"Oh. It's just you, Percy." Percy scowled.

"I wonder if that invisible engine will come visit the Earl's museum once it's open!" Millie mused to Stephen at Ulfstead Castle, "Seems like it'd be better than living in a cramped steelworks anyway." Neither noticed Percy dropping off some trucks and immediately leaving. To make matters worse for Percy, he didn't actually see any sign of the invisible engine all day. He grew more and more frustrated.

At last, Percy arrived at Tidmouth Sheds for the night. He rolled onto the turntable and yawned, eager to forget about the invisible engine. However…

"That new engine is an odd one, isn't he?" Henry thought aloud.

"He is quite the character," Edward chuckled, "but he seems very nice." Henry grunted.

"Even so, he never stops talking. How did you two manage to put up with him?" he asked Thomas and James. James rolled his eyes.

"I'm still asking myself that."

"He may be a bit… eccentric," Thomas admitted, "but he's a good friend and-" Percy groaned as he backed into his berth.

"Ugh, enough about the 'invisible engine!' That's all any of you talk about!" Thomas and James shared a look. Thomas opened his mouth to speak but James cut him off.

"Well, an invisible engine would be big news, wouldn't it?" he smirked.

"But it's not fair!" Percy complained, "I didn't even get to see him! Why can't I?"

"You just said it, Percy. He's invisible. Therefore, you can't see him." James laughed, making Percy grit his teeth.

"Why? You all seemed to have seen him! I want to meet him too!"

"Never mind, Percy," put in Thomas before James could reply, "He told me he's going to be working here all day tomorrow. I'm sure you'll see him at least once." Percy gave a small smile. James started to laugh again.

"Or not!" Percy's smile disappeared as he harrumphed and reversed further into the shed. Thomas glared at James.

"Why didn't you let me explain Merlin's not actually invisible?" he whispered hoarsely. James snickered.

"Let him believe what he wants to. He'll find out one way or another." Thomas looked back at Percy, who was now fast asleep, and sighed dully.

Merlin had slept in the yard during the night, and the next morning, was searching for something to do. He saw a long line of trucks and gasped excitedly, only to frown as Henry backed down onto them and puffed away.

"Oh dear… I need a bit of excitement." Suddenly, Merlin spotted Thomas coupling up to Annie and Clarabel and grinned.

"Thomas!" Thomas looked up and smiled as Merlin pulled alongside.

"Hello again, Thomas! It's been a while, hasn't it? Have you been on any big adventures lately?"

"Not since my journey beyond Sodor. Why do you ask?"

"I was just wondering if we could go on an adventure of our own today! Explore the island together! Wouldn't that be fun?"

"Um…" Almost immediately, Annie and Clarabel sternly cleared their throats from behind him.

"Don't you even think about it!" Annie scolded, "We have a duty to our passengers!"

"Quite right, Annie," Clarabel agreed, "It simply wouldn't do you for to gallivant off again." Thomas smiled sheepishly at Merlin.

"Sorry, Merlin." Merlin chuckled sadly.

"Oh… I understand. Ah well. Maybe some other time." He whistled and steamed away, leaving a concerned Thomas and a relieved Annie and Clarabel behind.

Merlin rolled through the junction and up to Knapford, hoping there would be something exciting there. Instead, he saw a little green engine sitting in the station, intensely scanning the platforms. Curiously, Merlin trundled forward.

"Hello there!" Percy jumped in surprise. "Oh, sorry, didn't mean to scare you. But what are you doing?"

"I'm looking for an engine. I'm sure he's around here somewhere." Percy glared at the farthest platform. "I know you're there!" he called, only to groan in disappointment as it turned out to be Philip shunting some coaches. Merlin watched with interest.

"An engine? What does he look like?"

"That's the thing; I don't know! It's an engine no one can see!" Merlin gasped.

"An engine no one can see? Oh my! That sounds very exciting!" Percy scoffed.

"It would be… if I could find him." Merlin thought for a moment.

"You know, searching for an engine you can't see is no easy task; I would know. If you'd like, I can help you look for him!" Percy was surprised.

"Really? You'd do that?"

"Of course! It'd be a grand adventure, I'd say!" Merlin whistled and started reversing away. "Come on! I know all the best hiding spots that engine could be hiding in!" Percy grinned and quickly followed.

Together, Percy and Merlin looked all around the railway, searching for any possible sign of the invisible engine. First, they tried the Steamworks. Percy frowned as Merlin was lifted up into the air by the hoist. The two heard the clearing of a throat and Victor rolled up, looking very annoyed. Percy and Merlin smiled sheepishly. Cranky was unloading crates at Brendam Docks when, upon lifting one particularly large one, Merlin was underneath. Cranky gaped. At the scrapyard, Reg was singing to himself as usual, grabbing a large pile of scrap with his crane arm. He immediately dropped it as hiding underneath it was Merlin.

Merlin and Percy rolled along the main line, each looking rather dejected.

"As much as I hate to say this, we're having no luck finding this elusive fellow," Merlin sighed. A wide smile crossed his face. "I know! How about we split up? We can cover more ground that way."

"Good idea, Merlin! I'll check down the branch line!" Percy whistled and hurried into Knapford before racing down the junction to Thomas' line. The tank engine in question raised an eyebrow as he flew past.

"Percy?" Thomas looked ahead to see Merlin rolling in.

"Merlin?"

"Ah, Thomas! Have you seen an engine lately?" Thomas frowned, perplexed.

"I've seen many engines today, Merlin."

"No, no, that's not what I mean. Percy and I are looking for an engine you can't see. I was wondering if you know where he is?" Thomas shared a glance with Annie and Clarabel. Immediately, he realized what had happened.

"Oh, bother that James…" he muttered crossly, "I'll give him a piece of my mind next time I see him."

"James? What did he do? Did he see him?" Thomas looked around to make sure Percy wasn't around to hear.

"Merlin, I'm not sure how to say this, but… you said he was 'an engine you can't see'?"

"Yes?" Merlin asked expectantly.

"Well, that means they're… invisible." Merlin blinked.

"Wait… you mean all day I was looking for… myself?"

"I suppose you could say that-" Merlin's laughter cut Thomas off.

"Oh, how brilliant! I'm so elusive I've even tricked myself! I didn't realize I was that good!" He suddenly stopped as a thought struck him.

"But what am I going to tell Percy? He's been seeing me all day; he won't believe me if I say I'm invisible now!" Thomas tried to speak but Merlin interrupted.

"Oh, I know! I can pretend to be the engine we were looking for! If Lexi can change voices, so can I! Thanks, Thomas!" Merlin whistled and rolled away, leaving Thomas to watch in horror.

"...oh no."

Percy had had no luck as he searched Thomas' Branch Line, and was returning to the station to regroup with Merlin. He sighed to himself as he stopped at a red signal.

"All this for nothing… I hope at least Merlin found something."

"Percy!" came a raspy voice Percy had never heard before. He jumped and looked around.

"H-Hello?" Percy called nervously, "Is someone there?"

"Why, yes! I've heard you've been looking for me!" Percy's eyes lit up like stars as a cloud of steam came closer to him. The rails creaked under the weight of the heavy engine.

"I-Is it really you?"

"Of course it's me, Percy! I must say, I'm very flattered you were so interested in me!" Percy could hardly believe what he was hearing.

"Well, everyone is too! You're the talk of the island! Now, I can see why!" Percy grinned, "What's your name?"

"Uh… Me… Mar… lin… tin... Martin… Yes, Martin!" The voice seemed unsure of itself, but Percy didn't notice. He was about to reply when the voice cut in. "I'm afraid I've got to go now, Percy. I'm only a visitor, you see." Percy's face fell.

"Oh… Goodbye, Martin!"

"Farewell, Percy! Dry rails and good running to you!" The cloud of steam backed away until it was out of sight. Percy was very giddy as the signal dropped.

"That was him! Really him! To think he was here all along! Just wait until I tell Merlin!" He whistled and hurried away, passing a siding hidden by trees. In the siding, Merlin sighed with relief and smiled.

Percy raced back up the line as quickly as he could. He pulled into Knapford, panting heavily.

"Merlin? Merlin! Guess what?"

"What is it, Percy?" Percy jumped as Merlin was suddenly right beside him. Nonetheless, Percy smiled giddily.

"I saw him, Merlin! I saw him! You just missed him! He was just a short ways down Thomas' line!" Merlin chuckled.

"That's wonderful, Percy! I knew you could find him! I suppose this concludes our adventure, doesn't it?"

"Yes, but it was a lot of fun, Merlin! Maybe when you next come to Sodor, we can have another one!" Merlin grinned.

"I'd like that a lot, Percy." He whistled and rolled away, leaving Percy to sigh happily. Unbeknownst to them, Thomas and James had been watching from the yard and had heard everything. Thomas chuckled.

"Well, well, well! What do you think of that, James?" James was too stunned to say anything.

Later that day, Merlin had to return home to the Steelworks. Thomas and James waited at Vicarstown Station to see him off.

"Sorry Percy couldn't come, Merlin, but he offered to take my train for me," Thomas said apologetically.

"Never mind, Thomas; I'm sure we'll see each other again very soon! ...provided Frankie doesn't tear my tender off when I get back." Merlin and Thomas laughed, though James merely chuckled awkwardly.

"Well, goodbye, Merlin. It was fun having you here."

"Uh… sure, what he said," James added quickly. Merlin chuckled.

"Thank you both! Farewell, friends! I'll come back as soon as I can!" He whistled loud and long and roared out of the station. As he approached the Vicarstown Bridge, Samson was coming the other way with a goods train, who was too busy talking to Bradford to notice him.

"Bradford, please, I know there's a signal up ahead, you don't need to tell me."

"I clearly do, boyo. You don't have a good enough record to think otherwise." On the other line, Merlin grinned.

"Invisibility, on!" Steam erupted from Merlin's funnels, covering Samson and Bradford in a cloud of steam.

"Look sharp, Samson! We've been ambushed!" Bradford coughed as the steam slowly started to dissipate, "Show yourself, you delinquent!" But Merlin had already gone.

Author's Note: Originally I was going to post a different rewrite to make them in the same order as the season, but I figured it made more sense to post them in order of when they were written. This one was written back in January 2019, so much more recent than the previous. This one was a fun one, particularly because of Merlin. I decided to give him a more proactive role here, since in the episode itself, he's more of an observer than anything. Speaking of Merlin, it was fun trying to figure out how to write him, and I think I did a decent job. As hinted at towards the end, Merlin will appear again in my original stories. When, I don't know, but it'll happen. The other Steelworks engines may appear too, who knows. More differences include the omission of Trevor, since he didn't really fit the new plot I had created, and the new plot itself, which is Percy and Merlin together trying to find the "invisible engine", which I think is a much funner premise than what the episode had, but ah well, timeframes and all that. This also had a pretty diverse cast (for CGI standards anyway) with Millie, Den and Dart, Sidney, Paxton, Bradford, Victor and Reg making brief appearances. It was fun giving some of these characters more to do than they had in the season proper, which will become a bit of a common theme during the rest of these rewrites.