Carly and Dash sat still for a moment, gazing out at the Tundra landscape. Wind whistled around them and blew spirals of snow into the air. Carly spoke into her transmitter, and Dash heard her voice as if she were speaking right next to his ear. “First on the agenda,” she said. “The cave.”

“Right,” said Dash. He checked his MTB and read out the coordinates that Chris had provided.

Carly pressed a button, and the motor roared. The Streak leaned and turned. Dash could see nothing but white, white, and more white as they sped along, until suddenly a strip of black rock would rear up and be gone, or they’d pass a snowdrift shaped by the wind into peaks with blue shadows. Ridges of jagged ice, cliffs that seemed to rise out of nowhere—it was a rugged landscape, where fast travel was perilous.

And yet Carly kept the racer moving at incredible speed. “I love this!” she cried. She ran the Streak up a slope and over the top, and for a few seconds, they were airborne. “Wheee!”

When they’d been speeding along for five or six minutes, Dash noticed that they were picking up a heat signal. “Slow down for a minute,” he said. “Something’s out there.”

Carly braked. “What is it?”

“I don’t know. Look at this reading.” He held out his wrist.

“Maybe an ice crawler?”

“I don’t think so. This thing is moving faster than any animal would.”

Carly changed course, and they headed toward the signal. It wasn’t long before they saw a dark dot speeding across the landscape. It could be only one thing.

“The Light Blade team,” Dash said. “They got here before us.”

Carly’s voice sounded grim in Dash’s ear. “All right,” she said, “they’re here, but they haven’t found the cave. They’re in the wrong place. We’ll get there before them.”

She stepped on the accelerator. The engine roared and screamed as Carly swung around a sharp curve.

Dash’s heart was racing—full of adrenaline. This is awesome, he thought, but the next moment, when he glanced down at the map, a shock ran through him. “Carly, look out! Straight ahead—a crevasse! Slow down!”

Carly veered sharp right. The brakes squealed, and the racer stopped in a cloud of snow. They turned to look at each other, wide-eyed. Carly moved the Streak forward an inch at a time, until they were right at the edge of the great crack in the ice—sheer walls of deep blue plunged to an invisible bottom.

They were silent for a moment.

“We can do it easily,” Carly said.

“You’re sure?”

“Sure. I’ve jumped wider ones a hundred times on the simulator. We just have to get up speed. Come on.”

She turned the Streak and drove it back the way they’d come for half a mile, then turned again in the direction of the crevasse. Dash watched the speedometer—sixty miles per hour, sixty-five, seventy—and then looked through the windshield to see the lip of the yawning crack straight ahead, and suddenly, there was air beneath them, deep blue fathoms of it. But before he knew it, the white ground was below them again, the landing so smooth and soft he hardly felt it.

Carly grinned and kept going. Dash gave her a quick, happy punch in the arm.

For a while, they sped across the snow easily, like expert skiers, riding the curves, catching air on the high dunes, never slackening their speed. Dash sat back; his tension drained away.

They crested a hill, and Dash looked out toward the horizon and saw pale, cloudlike columns rising against the sky, dipping and twirling and bending like mile-high dancers. They moved together, in an unruly crowd, maybe fifty of them, maybe more, sweeping across the snowy land toward a region of low hills.

“Uh-oh,” said Carly. “Look.” She pointed to the west, where a line of darkness showed above the mountains.

“A storm,” said Dash. “Do you think we’re headed for it?”

“I think it’s headed for us,” Carly answered, and immediately, Dash could see that it was. The dark line was rising, covering more and more of the sky.

“The wind’s picking up,” Carly said. “I can feel it trying to blow us sideways.” She tightened her grip on the steering wheel.

Snow struck against the windshield, hard, like little pebbles, and the clouds came lower, and then they were inside the blizzard. Wind drove the snow at them in a blinding spiral.

“I can’t see anything!” Carly wrestled with the steering wheel, trying to steady the Streak against the wind howling around them. “We have to slow down.”

Dash pressed against the glass, squinting, trying to see through the swirling white. “Looks like a gap in the cliff up ahead,” he said, pointing. “Can we get there?”

“I don’t know!” Carly’s voice had an edge of fear. “This wind! It’s so strong!”

The noise was thunderous. A powerful gust struck them from the side, and Dash felt the Streak tipping him toward the ground. “We’re going over!” he shouted.

Carly fought hard, but when the wind caught their underside, it pushed full force, and the snowmobile leaned and fell, leaving them sitting sideways, strapped into their seats, one above the other. The driver’s side door was now the roof door.

Carly clicked its lock and pushed upward with all her might. The door sprang open, letting in showers of snow. “Climbing out!” Carly radioed. She undid her seat belt and gripped the edge of the door and hoisted herself through, feeling a moment of gratitude for all those pull-ups STEAM had made her do. Lying across the Streak’s side, she stretched an arm down toward Dash. He grabbed her hand, she pulled, and he made his way up and out.

What struck him first was not the wind, not the driving snow, but the cold. It seemed to come right through his protective suit and find its way into his bones. He was stunned by it.

They both were.

But they had to move. They dropped down to ground level and stood beside the Streak, which lay with its runners facing them. “Grab the top runner,” Dash said. Carly did, and he did too, and they both pulled on it with all their strength. But the Streak, though it ran across snow as lightly as a water spider, was built of heavy stuff, and they couldn’t budge it. They walked around it and tried hoisting it up from the other side. “Look,” said Carly, “this whole part is already frozen into the snow.”

If they’d had a long board and a rock, they might have made a lever to lift the Streak, but Tundra was treeless. If they’d had a way to boil water, they might have freed the Streak by melting the ice that held it. But though they had water with them, they had no stove to heat it on. “We could make a fire,” said Dash, but without hope. What fire would survive in this wind?

They heard some scraping sounds, and in the open hatch of the Streak, a trapezoidal head appeared.

“TULIP!” cried Carly. “We forgot her!”

They lifted up TULIP’s heavy little body and set her down on the snow. Her belly glowed orange.

“Good call, Carly!” shouted Dash.

Carly smiled. “The cold never bothered me anyway.”

TULIP was already at work. Heat beamed out from her middle at the ice locking the Streak to the ground, and in a few minutes, the ice was water. Dash and Carly slid their fat-gloved hands underneath, found the ridge at the top of the window, and pulled with all their might. When the ship came free, they backed up to it and pushed with the force of their whole bodies. The Streak groaned, creaked, and at last sat upright on its runners.

Carly cheered. “Done!” she cried out. “Let’s go!”

But Dash stood still. A wave of weakness swept over him. His body felt heavy as stone. He couldn’t show Carly he was breaking down, so he leaned against a snowbank and pretended to be tinkering with his wrist tech settings. “Hold on a second,” he said. “I need to make an adjustment here.” His heart was pounding at his ribs—thud, thud, thud—way too fast.

“What adjustment? What’s wrong?”

“Just have to get these coordinates…” Breathe, he told himself.

“Do it while we ride!” yelled Carly. “We have to hurry!”

But it was several seconds before Dash could make his legs move. By the time he got into the Streak and fastened his straps, Carly was vibrating with impatience. “I don’t understand what took so long,” she said.

Dash spoke as strongly as he could, which was hard, knowing he was lying. “I had to get the settings right. It’s tough to do it when we’re going a thousand miles an hour.”

For a second, they scowled at each other.

But there was no time for that. The next second, they were off again, moving slowly at first through the diminishing storm, and then fast as the storm passed over them and they came into the clear.

Carly resumed top speed. They followed the route through the valley, climbed toward the mountain pass, and after some wrong turns and mistaken stops, they came to the dark mouth of a cave at the top of a long, boulder-strewn slope. It would have been a moment to celebrate except for one thing: the snowmobile from the Light Blade was already there.