It was the day of the Summer Festival in Kirkby Stephen, and the engines were happy. There were going to be rides, a band, a parade and fancy decorations. Tracy was very excited. This year, there was going to be a new attraction. A hot air balloon would be giving rides to visitors and Tracy had never seen one before.

When Tracy arrived at the Station with her passengers, she saw a beautiful sight up in the sky. It looked like a giant red and yellow balloon, but instead of a string, it had a basket on the bottom with people in it. "Wow! is that the hot air balloon?"

"It is," said her Driver. "Isn't it a lovely sight?"

"How can people ride up there without flying too high?"

"Attached to the basket is a blower that makes a very hot fire," her Driver explained. "That's what makes the balloon fly. When the fire gets smaller, the air in the balloon cools and it gently floats downward. That's because hot air rises while cold air sinks." Tracy was impressed as she watched the hot air balloon drift slowly to the ground.

Suddenly, a big gust of wind blew up and the balloon started to drift sideways. Everyone gasped as the balloon floated towards a building. Thinking quickly, the Pilot made a bigger flame and the balloon rose higher, just missing the building.

"What's going on?" Tracy asked.

"It's the wind," said the Stationmaster worriedly. "It wasn't supposed to be this strong today."

Tracy saw the balloon drifting away. "Those people need help."

A siren sounded as two fire engines raced after it. "It seems the Firemen are on their way to rescue them."

"Can I help too? Not all roads come close to the railway."

"What a good idea, Tracy," agreed her Driver. The Stationmaster telephoned the Signalman and Tracy raced out of the Station as fast as she could.

Tracy followed the hot air balloon up to Shap Cutting. It was near a Quarry and had high rocky walls on either side of the line. "Oh no," puffed Tracy, "those rocks could rip a hole in the balloon. The passengers will be hurt."

"We're running low on fuel!" the Pilot called.

Then, Tracy had an idea. "Watch yourselves!" she shouted. She raced as close as she could and let out a huge burst of steam. It blew high into the air and into the balloon, making it rise higher and over the cutting.

"Well done, Tracy," called her Driver and the passengers cheered too.

Tracy raced on as the hot air balloon floated towards a part of the Dark Woods in Rydal. The wind was blowing the balloon towards the trees. "I'll let off some more steam!" she called.

"No!" shouted the Pilot, "the wind's too strong! I know what to do! Stay back!"

Tracy was worried. Suddenly, something fell to the ground and burst open. It was a bag of sand. Tracy watched as more sandbags fell from the balloon and it rose higher, just enough to fly over the trees. Tracy gave a sigh of relief. "Hurray!" she whistled.

Next, Tracy and the balloon approached a tunnel. The mountain was very high with very sharp rocks.

"Bust my buffers!" cried Tracy, "they're going to crash!"

"I don't think so," replied her Driver. "Watch." The wind blew stronger, and the balloon floated faster. Then…the balloon drifted sideways and around the side of the mountain. "You see? The wind can't go through the mountain, so it's going around it and taking the balloon with it." Tracy sighed and whooshed through the tunnel as fast as her pistons would pump.

Finally, the wind slowed down and so did the hot air balloon. "Are you alright?!" Tracy called.

"We're fine," shouted the Pilot, "but we're very low on fuel now! We'll have to land, but the wind may blow us away again!"

Then, Tracy had another idea. "Maybe you won't have to land! If you drop a rope down to me, I can pull you back to Kirkby Stephen!" And everyone agreed.

The Pilot dropped two strong cables and when the Firemen arrived, they helped attach them to Tracy. Tracy whistled bravely and puffed away pulling the hot air balloon behind her.

Tracy pulled the balloon along a different route with no trees or high rocks, but it was a long journey, and she knew the blower would run out of fuel soon. Luckily, Kana arrived carrying more visitors for the Festival. Tracy was coupled up and they made it back to Kirkby Stephen just in time. Everyone cheered as the engines rolled in and the hot air balloon was pulled safely to the ground.

"Well done, Tracy," said the Tall Controller. "I see it was a good thing you went to help after all. I am very proud of you."

"Thank you, Sir."

"And thank you, Tracy, for being there for us," agreed the Pilot.

Everyone cheered again as the band started to play and Tracy smiled happily as she whistled along.