A team of animals with axes and ropes charged into the arena to free the still-wedged bear. The girls and Thunder also rushed over and gathered round, anxious the polar bear might be stuck inside for ever. It took some digging and pulling but suddenly the bear shot from the tunnel like a cork from a bottle. As soon as it was free, Thunder was presented with his winner’s medal to rapturous applause. Even the polar bear went over to shake his paw.

“Thunder, you did it, you did it!” cried Katy, holding her cat above her head in celebration.

“Katy, please put me down,” Thunder grumbled, not used to the attention. “Anyway, don’t you mean, we did it?”

Cassandra nodded. “We couldn’t have done it without Zia’s idea. How did you know, Zia?”

“It was just something Thunder said. That we’re all good at different things.” She grinned. “It occurred to me that he’s right and we’re all talented in different ways.”

They stopped chatting then because Pilar was coming over with her fellow council members.

“Congratulations,” the polar bear said with a deep chuckle. The atmosphere between the bear and the girls was friendlier now, less suspicious. “You’ve impressed us today. You’ve showed tremendous determination. But you said you wanted to teach us an important lesson. Please, explain.”

“It’s simple really.” Zia felt her insides swell with pride. “Arctic animals are adapted for life on snow and ice, but their abilities are shaped by the world around them. An animal may be good at swimming, but that’s no use if it has to move on land. An animal may be brilliant at jumping, but that’s no use if it has to travel in water. This competition has made me realise that every habitat is important, because every creature needs their own habitat to survive!”

Pilar’s grin widened and for the first time Zia didn’t feel scared of the bear.

“You’re right. That is a valuable lesson.” She chuckled again, her big belly bouncing up and down. “And you’ve taught us that not all humans are bad!” She winked and then presented them with three more snowflake-shaped ice medals like the one that hung around Thunder’s neck.

“You’ve all earned these. Wear them well,” she said, placing them over the girls’ heads, “and always remember the things humans can do to protect the Arctic. You see, if more humans – courageous and intelligent humans like you – truly understand the damage being done to our planet and try to do something about it, the world might begin to heal. Did you know that burning fossil fuels such as oil and gas is one of the biggest causes of climate change, because of the amount of carbon dioxide released into the atmosphere? This is why the ice caps are disappearing and with them the homes of the animals you see around you. How would humans like it if their homes starting melting away?”

The girls hung their heads.

“So the more people you tell about this, the more chance we have of reversing the Great Melt. Now come,” said Pilar, changing the mood with a warm smile. “It’s time to eat. This has been a truly special winter games!”

The girls and Thunder followed Pilar back through the frozen archway, where in front of them hundreds of animals were sitting around the biggest picnic blanket Zia had ever seen. The blanket was made of ice, with delicate snowflakes engraved upon its surface that glittered and twinkled like stars. But it’s what covered the blanket that excited the girls the most: the finest spread of food they’d ever seen. There were snowflake-shaped sandwiches, cakes with blue icing, donuts with blue and silver frosting and, most brilliant of all, mountains and mountains of silvery-blue ice cream!

“A North Pole picnic!” squealed Zia, smiling at her friends. “We get to have our picnic after all!”

Cassandra, Katy and Thunder beamed and looked as eager as Zia to start eating.

“Please, help yourselves,” Pilar said kindly.

“Oh, we brought some things too!” said Zia, suddenly remembering the emergency snacks they’d packed for their adventure. She reached into her rucksack and pulled out the chocolate bars and sweets to share with their new friends.

Pilar nodded in approval, and they all dived in, loading their plates to the brim. Only when they couldn’t fit anything else in their stomachs, Zia turned to Pilar.

“Thank you, for everything,” she said, swallowing her final mouthful. “We’ll never forget our trip to the Arctic, or you, or this picnic. How can we ever thank you?”

Pilar smiled. “The lesson we’ve learned is a great place to start.” She gestured to all the animals around them. “Our differences need to be celebrated. And every homeland needs our protection. This is what you need to think about and take home to your friends and family. Will you do that for me? For all of us?”

“We will, we promise,” the girls said together.

“I’ll make certain they will!” Thunder added, trying to make himself useful.

Everything Pilar had told them chimed exactly with what Ms Coco had taught them about the responsibility we have as humans to protect our planet. Seeing the North Pole melting for themselves, and knowing these animals were at real risk of losing their habitat, made the girls even more determined to share this message with the world.

“Remember our lesson at school,” Zia said, turning to Katy and Cassandra, “when we talked about the things we can do to help combat climate change?”

“Like using less energy?” Cassandra asked.

“Exactly,” said Zia. “Simple things, really, like walking or cycling to school rather than taking the car, which burns petrol or diesel and releases harmful gases into the atmosphere.”

“Or turning lights off when we leave a room, so we use less electricity?” offered Katy.

“Yes, and turning the TV off rather than leaving it on standby,” said Zia.

“How about eating less meat?” asked Cassandra. “I’m sure I remember learning that cows release methane from their bottoms!”

“Oh yes, that’s right!” said Zia. “The more cows that are farmed, the more methane in the atmosphere. And too much methane also causes climate change!”

“There’s recycling too, of course,” said Katy. “If we reuse and recycle, less energy is needed to make things in the first place. And there’s a lot less waste!”

“You’ve got it!” said Pilar, listening in to their conversation. “There really is so much you can do.”

“Don’t forget equal rights for animals,” offered Thunder seriously.

Katy grinned, then ruffled Thunder’s head. “I’ll tell that to the next mouse or bird you catch in the garden, shall I?”

Everyone laughed.

“It’s good to know not all humans are intent on destroying our planet.” Pilar smiled gratefully. “And if you can share these thoughts with others, there might be a chance to turn the planet’s fortunes around. Now, are you ready to say goodbye?”

They all nodded their heads slowly, while Pilar pulled them into a warm bear hug. They felt sad to leave, but it really was time to go – they had an important job to do! When Pilar released them, the girls moved into a circle, Thunder in the middle, and held each other’s hands. Then they squeezed their eyes tightly closed.

“Now, repeat after me: I wish to go home,” said Pilar.

“I wish to go home,” they said together.

In an instant, electricity started pulsing through their bodies. They felt hot, then cold, then hot again, like their insides were filled with bubbles. When at last those feelings had passed, they opened their eyes.

They were still standing in a circle, only now they were surrounded by white sheets and duvets rather than soft, powdery snow. Outside it was dark, snowflakes falling and settling on the windowsill, and Thunder was meowing and cleaning his ears with his paw.

“It happened again!” Katy said, swishing her ponytail round as she looked down at her normal clothes.

“Hey, look!” Cassandra was holding a small silver snowflake in the palm of her hand. “The medal – I think it’s shrunk!”

“I know what that is!” cried Zia, examining her own tiny medal. “It’s a charm – like the star we brought home from the Wishing Star. Don’t you see? We can add these to our bracelets, and they’ll remind us of the lesson we learned at the North Pole!”

They helped each other secure the snowflake charms to their bracelets, while Katy helped fix Thunder’s to his collar.

“Where to next?” asked Zia.

“It’s your turn for a playdate, Cassie. Any ideas?” Katy asked.

Cassandra thought for a moment. “I do, but it’s going to be a surprise.” She grinned.

“Not even a clue?” asked Zia.

“Let’s just say, we might need swimming things again!” Cassandra laughed.

“Brilliant!” Katy clapped her hands, although Thunder didn’t look so pleased.

Zia paused for a second, thinking about everything they’d been through and everything they’d just learned. She took her friends’ hands in her own.

“As long as we’re together,” she said, “I really don’t mind.”