Justin Clarke tugged his gloves under the sleeves of his heavy blue parka. Then he shielded his eyes with one hand and searched all around. “I don’t see Dad,” he told his sister, Marissa. “Do you?”

“I can’t see anything!” Marissa cried, shouting over the wind. “All I can see is ice!”

The sled dogs barked and shook themselves, eager to start moving again.

Justin narrowed his eyes, squinting to the right, then the left. The ice stretched smooth and shiny, silvery under the bright sunlight.

In the distance, it darkened to blue. Darker. Darker. Until the blue ice appeared to melt into the sky. Justin couldn’t see where the ice ended and the sky began.

“It’s cold,” Marissa murmured. A sharp gust of wind blew the parka hood off her red hair. She instantly reached up with both gloved hands and pulled it back in place.

Justin rubbed his stub of a nose. He pressed his furry gloves against his frozen cheeks, trying to warm them.

The dogs tugged. Justin grabbed the handle of the dogsled to keep it from sliding away.

“What do we do now?” Marissa asked. Justin could hear a slight tremble in her voice. He knew his sister was as frightened as he was.

He stepped onto the sled runner. “Keep going, I guess. Keep going until we find Dad.”

Marissa shook her head. She held her hood in place with both hands. “Maybe we should stay right here,” she suggested. “If we stay here, it will be easier for Dad to find us.”

Justin stared hard at her. Why does Marissa look so different? he wondered. Then he realized—the cold had made her freckles disappear!

“It’s too cold to stay in one place,” he said. “It will be warmer if we keep moving.”

He helped her onto the back of the sled. At twelve, he was only a year older than Marissa. But he was big and athletic, and she was tiny and skinny.

The dogs grunted and impatiently pawed the silvery ice.

“I hate Antarctica!” Marissa wailed, grabbing the sled handle with both hands. “I hate everything about it. I can’t even spell it!”

Uh-oh, thought Justin. Here she goes. Once Marissa started complaining, she never stopped.

“We’ll be okay,” he said quickly. “As soon as we find Dad, everything will be okay. And we’ll have some amazing adventures.”

“I hate amazing adventures!” Marissa declared. “Almost as much as I hate Antarctica! I can’t believe he brought us to this awful place—and then lost us!”

Justin gazed up at the sky. The sun had started to set. Wide streaks of golden light sparkled over the ice.

“We’ll find Dad really soon,” he told Marissa. “I know we will.” He lowered the hood over his forehead. “Let’s get going, okay? Before we freeze.” He snapped the line and, in a deep voice, called out to the six dogs, “Mush! Mush!”

The dogs lowered their heads and moved forward with a burst of speed. The sled jerked hard as it started to slide.

“Whoooooaaa!”

Justin let out a startled shriek as he felt himself start to fall.

His gloved hands flew off the sled handle. He frantically groped for it.

Missed.

And fell off the sled. He fell hard onto his back on the ice.

“Ooooof!” He felt the breath whoosh from his lungs.

His arms and legs kicked the air, like a bug on its back.

He struggled to a sitting position. Blinking. The ice shimmering all around him. Shimmering so brightly, he could barely see the sled as it sped away.

“Justin—I can’t stop it!” Marissa’s shrill shriek sounded tiny against the steady rush of cold wind.

“Marissa—!” He tried to call to her.

“I can’t stop it! Help me! Help!” Her cry already so far away.