It was a sunny, summer day on the Island of Sodor. Billy and Charlie were puffing along the line together and Charlie was telling one of his jokes.

"Okay, Billy. Why did the Stationmaster throw his clock out the window?"

"Um…I don't know, Charlie."

"He wanted to see time fly!" And the two engines laughed.

Charlie was on his way to the Steamworks. He had been helping Mavis at Ffarqhuar Quarry and his paint had been scratched and pelted.

When Charlie puffed in, he noticed Victor wasn't there. "Kevin, where's Victor?" he asked.

"He had to leave for a while, but he told me you were coming in for a repaint." Charlie stopped on a siding and his fire was put out, but then Kevin rolled up looking worried. "I'm sorry, Charlie. There isn't much purple paint left. We won't have more until tomorrow."

Charlie was worried. "But I have to take passengers to the seaside tomorrow morning. I can't go like this." Then, an idea flew into Charlie's funnel. "Kevin, can I be painted a different colour?"

Kevin wasn't sure. "What colour would you like?"

"Can I be painted orange with green and yellow stripes like Billy? Then, when the children see me coming, they will think I'm Billy when it's really me and it will make them laugh."

Kevin still wasn't sure, but he didn't want Charlie to collect his passengers with scratched paint. "Okay, Charlie…if that's what you want."

The next morning, Thomas was at Kellsthorpe Station. He knew Charlie had to be there to collect his passengers, but Charlie was nowhere to be seen. Soon, Thomas saw an orange tank engine backing down onto Charlie's coaches. "Billy," he called, "why are you collecting Charlie's coaches?"

Then, Thomas heard laughing. "I'm not Billy! I'm Charlie!"

Thomas blinked. It was Charlie, but he was wearing Billy's colours. "Why are you wearing Billy's paint?" Thomas asked.

"They were out of purple paint at the Steamworks," Charlie explained, "and I thought being painted like Billy would be funny." Sure enough, all the passengers started laughing.

"Well, it is a little funny," said Thomas.

As Charlie puffed along the main line, he saw children watching him from bridges and beside the track. When they saw him, they thought he was Billy. "Hello, Billy!" they would call.

And Charlie would call back, "I'm not Billy. I'm Charlie," and they all laughed.

As Charlie continued on his journey, he suddenly began to feel cool, and he started to go slower. "What's the matter," Charlie asked his Driver.

"You're almost out of coal," he said. "We'll have to get some more at the next station."

The Fireman was anxious. "If we make it there before we run out," he added.

Then there was trouble.

Charlie heard a whistle. James was coming up behind with some coaches and he slowed down as he approached. "Hurry up, slowcoach," he huffed. "I must get my passengers to the station on time."

But Charlie couldn't go any faster. Up ahead, he could see the junction they were supposed to take, but it seemed like a long way away. Luckily, it wasn't long before they reached it.

James was cross. "About time, Billy. You could've made me late."

Charlie laughed. "I'm not Billy. It's me, Charlie." But James was too far away to hear. Charlie was surprised. That's strange, he thought. Why wasn't James laughing?

Charlie managed to make it to the next station and filled up with more coal. Then, he raced as fast as he could to make up for lost time. Children still called out from the trackside thinking he was Billy, but Charlie didn't have time to answer.

At last, Charlie arrived at the Seaside Station, just in time. He was relieved, but as his passengers got off the train, he saw Billy on a siding. The Fat Controller was speaking to him, and he didn't look happy. "Billy, what is going on? James told me that you held him up on the main line when you were pulling coaches. You could have made him late, and why were you there in the first place? I sent you to deliver some goods to Brendam Docks."

"But, Sir," Billy replied, "I did take the goods to the Docks. I didn't see James today."

The Fat Controller frowned. "I'm very surprised at you, Billy. Really Useful Engines don't tell tales."

Charlie could hardly believe his ears. He had accidentally held James up and the Fat Controller was blaming Billy. Charlie didn't like seeing someone in trouble and quickly puffed to the siding. "Sir, Billy didn't hold James up on the main line. I did."

The Fat Controller stared. "Charlie, why are you wearing Billy's paint?"

Charlie then explained about how there was no purple paint left, how he thought being painted like Billy would be a great joke and that he was going slowly because he was low on coal. "It wasn't Billy's fault, Sir, and I saw him taking his goods this morning."

The Fat Controller thought. Then he smiled. "Well Billy, it seems I owe you an apology and Charlie, thank you for telling me what happened." He paused impressively. "But in the future, Charlie, if you want to be painted like another engine, please ask me or Victor first." Charlie smiled.

"You know," Billy added, "you do look silly." And everyone laughed.

The next day, Thomas and Charlie were collecting passengers again. As Thomas waited at the platform, he heard a familiar whistle and saw a purple tank engine backing into the station and this time, Thomas knew who it was. "Good morning, Charlie," he whistled. "It's nice to see you in your own colour again. How was it being painted like Billy for a day?"

Charlie smiled. "It was fun for a while, but I think I will stick with my own coat of paint from now on. Besides, orange isn't really my colour." And the two friends laughed and laughed as Charlie the playful, purple engine set off to the seaside.