I FOUND PIGGYBACKING much scarier than mammoth riding. Despite four human passengers and a frog, Big Mumma ran fast and furious—snout-plowing through thick foliage and even leaping over a creek as the pursuing Boar Riders nipped at her hooves.

After much cringing, ducking, and a good deal of terrified screaming, we approached my village. I ducked as Big Mumma charged under a low-hanging gourd tree and leapt into the public clearing, snorting to a halt just in front of the Shiny Stone. The Boar Riders followed suit. Soon Boss Hog, Snortimer, and a dozen other angry men on pigs surrounded us. The enormous Boss Hog looked particularly annoyed to be on a smaller sow than ours. His animal didn’t look too happy either.

The Macrauchenia Riders emerged from their caves and headed toward us, led by Boulder.

“Echo,” I muttered, “I really hope you have a plan.”

“Already happening,” she whispered. “Welcome to the first-ever Joint Clan Conference!”

“WHAT’S THIS?” Boulder barked at Boss Hog. “Why are you on my land, llama thief?”

Me?” said Boss Hog, working his pink jowls into a lather and pointing at us. “Your spies stole MY BOAR!”

“They’re not MY SPIES!”

“YES THEY ARE!”

“NO THEY’RE NOT!”

“YES THEY ARE!”

“NO THEY’RE NOT!”

“Great plan,” I whispered to Echo.

She shot me a withering look. “Do you have a better idea?”

“You mean better than listening to those two yell?”

“We just need to get them to realize that they face a much bigger threat than each other.”

“That would take a miracle,” I muttered.

A snowflake fluttered down from the sky and melted on my forehead.

Echo smiled.

“Huh?” said Boss Hog, peering up at the hazy late afternoon sky.

“What’s this white stuff?” muttered Boulder.

“Woolly calls it snow,” said Echo. “Well, snoooooooow.”

He ignored her.

I cleared my throat and turned to Boulder. “Remember the great storm I mentioned today? And the giant cats following the cold?”

Boulder looked like a dodo bird spotting the club that’s about to whack him.

Boss Hog looked at Echo with a similar expression. “It’s … all true?” he asked, his voice quavering.

She nodded.

Boulder closed his mouth and gulped. “When do the giant cats come?”

“Tomorrow,” I said. “Sunrise.”

In the Council Circle clearing just outside our village, I stood and listened intently to the first-ever Joint Clan Council.

“Don’t you see?” shouted Snortimer at his fellow Boar Rider councilmen. “This could all be some dirty Macrauchenia Riders’ trick to destroy our way of life! These Llama’s Boys hate our way of life!” He was saying this while shivering, as the snow piled on his own head.

When Boss Hog pointed this out, Snortimer snorted loudly and stormed off into the forest. I shook my head in amazement. It seemed that no amount of evidence was enough for some people.

“Boss Hog,” I said, “can we talk in private?”

The Big Man growled dismissively and pointed at his own head. “I’ve got some big thinking to do!”

“Well, I have a big thought for keeping the giant cats away,” I said. “At least for a while.”

“You?” he half laughed. “But you’re … little.”

“I’m aware of that,” I said. “But as my mother likes to say, sometimes big dodos grow out of small eggs.”

Boss Hog looked confused but grudgingly followed me out of the circle.

When we were out of earshot of the council, I stopped and turned to him. “Okay,” I said, “what is the one thing we humans have that giant cats don’t?”

He stared blankly at me. “I’ve never seen a giant cat.”

“Any cats, then.”

He scratched his forehead and shrugged.

“Hands!” I said. “They have paws, but we have hands. And that means we can throw things.”

He looked down at his own ham-sized mitts and furrowed his brow. “We throw giant cats?” he asked hopefully.

“No! We throw stones!”

A big childlike grin spread across his face. “I like to throw stones!”

“Good,” I said. “I want you to tell everyone to start gathering stones and piling them in each cave entrance. Then, at sunrise tomorrow, whenever a cat approaches one of our caves, the headstone players in the surrounding caves will pelt him.”

The Big Man still looked confused.

“We’ll throw stones,” I clarified. “At cats.”

He nodded. “Good plan.”

“Not really,” I admitted. “But at least it will give us some time to keep thinking. Also, we need to make sure everyone stays as warm as possible. Echo is working on that problem and—”

But Boss Hog was already waddling back to the Council Circle to present the throwing stones idea as his own.

Under the light of a thin ghostly moon, we all gathered stones. Echo pointed out that it would be much easier to work together and defend everyone in a single village, so Boss Hog sent Oinker and Newporker to bring the rest of their clan. She also pointed out that the more people gathered in the same caves, the warmer they could remain.

The snow slowly piled up in the public clearing, and the mounds of stones grew steadily taller in every cave entrance until they were halfway up to the ceilings.

At the first hint of dawn, everyone hurried inside. Most went toward the back of the caves, but Echo, Stony, and I and all of the headstone players positioned ourselves behind the various stone piles. Then we waited.

It wasn’t long before the chirping and buzzing of the morning forest went suddenly and uncannily silent. Without so much as a rustle, Smilus stalked out of the trees into the clearing. Every step he took, every motion he made, seemed effortlessly graceful, and I found myself wanting to paint him. Instead, I quietly picked up a stone from the nearby pile. Next to me, Echo and Stony did the same.

A dozen tigers slunk into the clearing after Smilus—their yellow, foot-long saber teeth glinting in the first rays of morning sun.

Smilus surveyed the humans in the caves. “Mmmmmmm,” he purred. “Looks like everyone’s staying for breakfast.”

The largest tigress licked her chops. Her cold green eyes were locked on Boss Hog, who was quivering like a bowl of lard in the leftmost cave. “That pink round one looks nice and juicy,” she hissed.

“He’s all yours,” said Smilus, turning toward us. “I’ll be starting out with these three bite-sized morsels.”

“And I’ve got dibs on that hairy one!” growled a cat with an extra-long left saber tooth and oddly crooked black stripes. He was ogling a quaking Boulder in the rightmost cave.

“Sure,” said Smilus. “Enjoy.”

A few of the other cats called out their choices. One licked his lips in my dad’s direction. Another salivated at the sight of Snortimer. And a buff young beast crunched his teeth at Bonehead.

“All right,” said Smilus, “it’s breakfast ti” He jumped back and snarled as my stone whizzed by him.

I swore under my breath.

Smilus’s eyes narrowed to black slits. Without a word, he leapt toward our cave.

Wap! Wap! A rapid volley thumped him left and right. Smilus took a couple of quick surprised steps backward. Stony and Echo grinned at each other and slapped hands.

Now the tigress sprang forward. Wap! A little stone bounced off her snout. She drew back.

“Chew on that, kitty!” shouted Hamhock, who had snuck up to our rock pile from the back of the cave where he was supposed to be.

And so it went for every cat: a leap forward, a volley of stones, a step or two backward.

But still—slowly, inexorably, the beasts crept toward the caves.

Soon, Smilus was close enough that I could see his oily hairs bristling. He smirked at me when he saw that there were no more rocks in our pile.

I stepped backward, wiping the sweat from my eyes.

“No need to wipe it away, Lug,” he said. “I like my humans nice and salty.”

Suddenly, I saw his left saber tooth splinter with a sickening crack. Echo had thrown the last stone in her hand. The tiger’s golden eyes blazed with fury.

Ladies first, then!” he hissed, leaping at her.

“No!” I cried, stepping between them.