But believing also meant her mother hadn’t died in the storm that had flattened houses in Barrow, Alaska, and buried half of Prudhoe Bay.

“Doubt your family, then, but believe your own eyes and ears.”

Her eyes told her he was an Ursus maritimus; her ears told her he was talking. Cassie squeezed her eyes shut. “You don’t exist.” She was deluding herself. Her senses were betraying her and making her believe something she’d given up believing more than a decade ago: that her mother was still alive. Cassie opened her eyes. The bear was still there.

“I am the polar bear,” he said, “and you are my bride.”

“No,” she said—no to him, no to this, no to everything.

His expression was unreadable. “Your mother made a promise.”

This was cruel. Simply cruel. “My mother is dead. Killed in a blizzard after I was born.” She felt her heart twist as she said it.

There was silence for a moment. Snow swirled around them—around Cassie and the giant polar bear—like in a snow globe. “Is that what you want?” the bear asked.

So softly that her voice barely carried beyond her face mask, she said, “No, of course not.” All her life, she’d wanted a mother. It was a hole inside her that nothing had ever filled. Not Dad. Not Gram. Not Max. Not any of the station staff who had come and gone.

“The North Wind did not kill her. He blew her to the trolls. For that, he has never forgiven himself.” The polar bear’s voice was a low rumble that rattled in her bones. Part of her wanted more than anything else to believe him. But she couldn’t let herself. Fact was fact; gone was gone. It didn’t matter how badly she wished it weren’t. “And I regret that the Winds found her, despite my best efforts.”

“Your best wasn’t good enough,” she said. She knew the words of the story: Bring me to my love and hide us from my father. If the story was true, then this polar bear had failed Cassie’s mother. If he’d done what he’d promised, Cassie would have had a mother.

“I did all I could.”

“Your promise is invalid,” she said. “You’ve no right to be here.”

“The promise holds,” he said in the same calm, impossible voice. “The North Wind would not have found her if it were not for his brother.”

He talked about the winds as if they were sentient. She squeezed her eyes shut. “You should have hidden her from him, too,” she said. “You failed.”

“I cannot leave the Arctic. I have responsibilities that I could not neglect,” he said. “I had to hide her in the ice. I am sorry.” For the first time, she heard a hint of emotion. That was almost as disturbing as the speech itself. He believed what he was saying. He believed her mother was alive.

“’Sorry’ doesn’t help,” she said. She tried to sound strong, but her voice betrayed her and cracked. Her heart beat so fast and loud that it thundered in her ears.

“If I could make it right, I would.”

Would he? Could he? “Would you free her from the ‘trolls’?”

His great jaws opened and shut, as if she had struck him speechless. She nearly smiled—she had flummoxed him. She’d turned the tables on the creature that was turning her world upside down. “You do not know what you are asking,” he said finally.

Oh, yes, she knew very well what she was asking: an impossibility. “Bring my mother back from the dead.” She felt light-headed as she said it.

“She is not dead.”

“That should make it easier.”

“I have responsibilities that I cannot risk.”

Without stopping to think, she said, “You free her from the trolls and I will marry you.”

For a long moment, he was silent. The northern lights filled the sky behind him. With his brilliant white coat and black unreadable eyes, he looked majestic and wild. Wind stirred his fur. “Is that a promise?” he asked at last.

Suddenly, it didn’t seem like a dream. It didn’t seem like a hallucination. It seemed real, overwhelmingly real. She put her hand on the station wall to steady herself. Her fingers were numb inside her mittens and gloves, and she felt her disbelief cracking as if her words had shattered it. Her mother… My mother is alive? And she had the opportunity to save her. Her head reeled. “Yes,” she said.

“Climb onto my back,” he said, kneeling in front of her.

She stared at him as the word “yes” rang in her head. Yes, she’d said. Yes, her mother was alive. Yes, Cassie would save her.

“I will carry you home,” he said.

She tried to read his inscrutable black eyes and failed. Her throat felt dry. She started to speak, swallowed, and then tried again. “Home?”

He inclined his massive head, and she shivered. “Your mother will be returned to the Arctic once our bargain is complete,” he said. “I will arrange it after we arrive.”

Wind whipped into her. Ice crystals pelted her parka. Gulping in burning air, she tried to nod as if she understood.

“Climb onto my back,” he repeated.

If her mother was alive, then she had been a prisoner for years and no one had rescued her. Dad had not rescued her. Dad had pretended she’d died. He’d kept this all a secret from Cassie.

Suddenly, she wanted to climb onto the bear’s back and ride as far away from the station as she could. She put her hand on his back and swung her leg over. She steadied herself. Oh, God, she was on a polar bear.

“Hold tight, beloved,” he said.

She gripped the bear’s neck fur as he carried her away from the only place she’d ever called home.

Latitude 76° 03’ 42” N

Longitude 150° 59’ 11” W

Altitude 5 ft.

The bear bounded through the snow. Cassie clutched his thick fur and clenched her teeth as the impact jarred her bones. Snow spewed out in waves.

“Are you afraid?” the bear shouted to her.

“Like hell I am.”

“Keep tight hold of my fur, and then there is no danger,” he said.

Impossibly, he increased speed. Blurring into white, the frozen sea rushed beneath them. She squeezed her eyes shut, and then opened them. Don’t think about the bear, she repeated to herself. Just focus on the ride.

The bear raced across the ice. Shadows streaked. Stars stretched into the comet tails of time-lapse photography. Faster and faster. She felt like she was flying. She was moving faster than a snowmobile, faster than Max’s Twin Otter. Wind buffeted her face mask, and she laughed out loud. She wanted to shout at the top of her lungs, Look at me! I’m faster than wind! Than sound! Than light! She felt as if she were light. She was an aurora streaking across the Arctic.

He ran on and on.

Eventually, as the stars faded and the sky lightened, she fell into a numb rhythm. Her pack bounced, bruising her shoulders rhythmically. She rode in silence, except for the harsh whistle of wind.

Several long hours later, Cassie heard ice crunch under the bear’s paws. Granules crackled in the monumental Arctic silence. She straightened and thumped her muscle-sore thighs. The bear had slowed and was simply walking now, across the shimmering frozen sea. The earth was painted in white and blue streaks of ice, reflecting the sky and the low, pale sun.

Squirming inside her parka, Cassie fished her GPS out of her inner pocket. She pressed the on button, and the signal flashed. She moved it back and forth, trying to get a clear reading. The longitude fluctuated wildly: 0° to 180°, as if she were at the North Pole. Worse, the latitude said 91°. This reading didn’t make sense. There couldn’t be a satellite over a location that didn’t exist. She shook the GPS, but the abnormal reading stayed. Cassie stared at it, and her heart started to thump faster. Either the GPS was malfunctioning or…

Or here was empirical proof that the impossible was real.

Cassie leaned forward and cleared her throat. “Excuse me… Um, where are we?”

“One mile north of the North Pole,” he said.