I’d like to thank the polar bears, arctic foxes, and caribou for their patience and kind words of encouragement during the writing of this book. I’d also like to thank my spectacular agent, Andrea Somberg, and my fabulous editor, Karen Wojtyla, as well as Sarah Payne, Emily Fabre, and all the other amazing people at Simon & Schuster. Special thanks as well to Tamora Pierce, Bruce Coville, and Thomas (Sully) Sullivan for all their advice and kindness.

Also, thanks to my friends for believing in me, especially Amy Johnson and Rick Keuler for all their encouraging e-mails, and thank you to everyone who answered my obscure research questions. Thank you as well to John Mastrobattista, Rob Harris, and my Target/Blackbaud team (past and present) for all their support.

And finally, many thanks and much love to my family. I am so lucky to have all of you in my life—the family I was born into, the family I married into, my wonderful children, and my dream-come-true husband. I love you all beyond the ends of the earth.

Once upon a time, the North Wind said to the Polar Bear King, ‘Steal me a daughter, and when she grows, she will be your bride.’”

Four-year-old Cassie clutched her quilt and stared at her grandmother. Tall and straight, Gram looked like a general. She perched stiffly on the edge of Cassie’s bed. She had a mahogany cane in her left hand. Tonight, Dad was away from the station, which meant Cassie would hear the story. Gram never told it when Dad was home. It was the only story she ever told.

“And so, the Polar Bear King kidnapped a human child and brought her to the North Wind, and she was raised with the North Wind as her father and the West, South, and East Winds as her uncles. She grew into a beautiful, but lonely, young woman. One day, while the Winds were gone (as they often were), she met a human man. She befriended him, and it wasn’t long before they fell in love.

“When the Polar Bear King came to claim his bride, she refused him. Her heart, she said, belonged to another. ‘I would not have an unwilling wife,’ he told her. ‘But your father has made a promise to me.’

“Knowing the power of a magic promise, the North Wind’s daughter sought to counter it with her own bargain. ‘Then I will make a promise to you,’ the North Wind’s daughter replied. ‘Bring me to my love and hide us from my father, and when I have a daughter, she will be your bride.’ And so, the Bear carried the North Wind’s daughter to her human husband and hid them in the ice and snow.

“Angry, the North Wind tore across the land, sea, and sky. But he could not find them. For a long while, the North Wind’s daughter and her husband were happy.

“In time, the woman had a child. Passing by, the West Wind heard the birth and hurried to tell the North Wind where his daughter could be found. With the strength of a thousand blizzards, the North Wind swooped down onto the house that held his daughter, her husband, and their newborn baby. He would have torn the house to shreds, but the woman ran outside. ‘Take me,’ she cried, ‘but leave my loved ones alone!’

“The North Wind blew her as far as he could—as far as the castle beyond the ends of the world. There, she fell to the ground and was captured by trolls.” Cassie heard the bed creak as Gram stood. Her rich voice was softer now. “It is said that when the wind howls from the north, it is for his lost daughter.”

Cassie blinked her eyes open. “And Mommy is still there?”

Gram was a shadow in the doorway. “Yes.”

Once upon a time, in a land far to the north, there lived a lovely maiden…

Latitude 72° 13’ 30” N

Longitude 152° 06’ 52” W

Altitude 3 ft.

Cassie killed the snowmobile engine.

Total silence, her favorite sound. Ice crystals spun in the Arctic air. Sparkling in the predawn light, they looked like diamond dust. Beneath her ice-encrusted face mask, she smiled. She loved this: just her, the ice, and the bear.

“Don’t move,” she whispered at the polar bear.

Cassie felt behind her and unhooked the rifle. Placid as a marble statue, the polar bear did not move. She loaded the tranquilizer dart by feel, her eyes never leaving the bear. White on white in an alcove of ice, he looked like a king on a throne. For an instant, Cassie imagined she could hear Gram’s voice, telling the story of the Polar Bear King… Gram hadn’t told that story since the day she’d left the research station, but Cassie still remembered every word of it. She used to believe it was true.

When she was little, Cassie used to stage practice rescue missions outside of Dad’s Arctic research station. She’d pile old snowmobile parts and broken generators to make the trolls’ castle, and then she’d scale the castle walls and tie up the “trolls” (old clothes stuffed with pillows) with climbing ropes. Once, Dad had caught her on the station roof with skis strapped to her feet, ready to ski beyond the ends of the earth to save her mom. He’d taken away Cassie’s skis and had forbidden Gram from telling the story. Not that that had slowed Cassie at all. She’d simply begged Gram to tell the story when Dad was away, and she’d invented a new game involving a canvas sail and an unused sled. Even after she’d understood the truth—that Gram’s story was merely a pretty way to say her mother had died—she’d continued to play the games.

Now I don’t need games, she thought with a grin. She snapped the syringe into place and lifted the gun up to her shoulder. And this bear, she thought, didn’t need any kid’s bedtime story to make him magnificent. He was as perfect as a textbook illustration: cream-colored with healthy musculature and no battle scars. If her estimates were correct, he’d be the largest polar bear on record. And she was the one who had found him.

Cassie cocked the tranquilizer gun, and the polar bear turned his head to look directly at her. She held her breath and didn’t move. Wind whistled, and loose snow swirled between her and the bear. Her heart thudded in her ears so loudly that she was certain he could hear it. This was it—the end of the chase. When she’d begun this chase, the aurora borealis had been dancing in the sky. She’d tracked him in its light for three miles north of the station. Loose sea ice had jostled at the shore, but she’d driven over it and then onto the pack ice. She’d followed him all the way here, to a jumble of ice blocks that looked like a miniature mountain range. She had no idea how he’d stayed so far ahead of her during the chase. Top speed for an adult male bear clocked at thirty miles per hour, and she’d run her snowmobile at sixty. Maybe the tracks hadn’t been as fresh as they’d looked, or maybe she’d discovered some kind of superfast bear. She grinned at the ridiculousness of that idea. Regardless of the explanation, the tracks had led her here to this beautiful, majestic, perfect bear. She’d won.

A moment later, the bear looked away across the frozen sea.

“You’re mine,” she whispered as she sighted down the barrel.

And the polar bear stepped into the ice. In one fluid motion, he rose and moved backward. It looked as if he were stepping into a cloud. His hind legs vanished into whiteness, and then his torso.