Magnus Frostbeard slammed his map on the tavern table and swore no one had crossed the frozen wastes and lived to draw it. He was short and stout, his beard heavy with old frost. For twenty years he had chased one rumor: a warm valley hidden at the heart of the ice, green and safe. He had the map half-charted. He did not have a crew, and no man could make that crossing alone. The tavern was warm and loud. Snow slid off its roof in wet clumps. Magnus stood on a bench and shouted his offer. He needed three strong bodies for a march into the deadly ice lands. A hunter laughed. A fisherman turned back to his ale. One old woman told him the cold had eaten his wits. "You want the valley," a deep voice said. "Everyone who wants it dies out there." Magnus turned. A white-furred were-bear filled the doorway, black eyes fixed on the map. This was Frost Thornpaw, a hunter Magnus had heard of but never met. Thornpaw crossed the room and pressed one clawed finger to the blank half of the chart. "You've never seen past this line. I have. I'll show you, if you can pay." "I can pay in a share of the valley," Magnus said. Thornpaw grunted. It sounded like agreement. A chair scraped. A huge troll woman rose from the corner, red braids swinging, her explorer's vest patched at both shoulders. Greta Stonebraid had listened the whole time. "A were-bear and a dwarf," she said. "You'll freeze without someone who can carry the load and dig you out of a drift." She dropped a coil of climbing rope on the table. "That's me. I go where the maps end." Magnus grinned into his beard. Two, and both worth ten. He needed one more. The door opened on a gust of snow. A small ice elf slipped inside, white hair wet, a thin blade at her hip. Frost Winterchase pressed her back to the wall and watched the room like a hunted thing. Her eyes stopped on Magnus's map. "You know the ice," Magnus said. It was not a question. "I was born in it," she said. "And I need to be gone from this town by morning." She looked at the door, then back at the map. "Take me across the wastes and I'll guide you through the crevasse fields. No one hunts a person out there." Magnus looked at the three of them. A were-bear, a troll, an elf on the run. Not the crew he had pictured. Better. "We leave at first light," he said, and rolled up the map. Winterchase went still. Boots stamped snow on the porch outside. Fists pounded the tavern door. A hard voice called her name and ordered it opened. She drew her blade. Magnus had his crew. Now they had to run before dawn.

They cleared the town in the dark, boots crunching hard snow. Magnus had planned to chart the way out by first light. The pursuers stole that from him. Now he led four people into open ice with a map that ended at the town's edge. He pulled his fur-lined coat tight and squinted at the black plain ahead. Two paths split the snow. He did not know either one. "Left," Magnus said, because a leader must say something. Greta Stonebraid stopped. The troll planted her feet and folded her thick arms. "You're guessing," she said. "I go where maps end, Frostbeard. But I don't die because a dwarf won't admit he's lost." Her red braids swung as she jerked her chin at the ground. "Read the snow first." Magnus felt his face burn under the frost in his beard. She was right, and that stung worse than the cold. Frost Thornpaw dropped to all fours ahead of them. The were-bear's white fur nearly vanished against the drift. He pressed his black nose to the crust and moved slow along the left path. Then he stopped and growled low. "Hollow," he said. "Ice over water. It won't hold Greta. It won't hold me." He backed away from the spot with careful paws. Magnus stared at the left path he had chosen. One more step and it would have swallowed them. Frost Winterchase pushed past him. The ice elf knelt at the fork and laid her small blue hand flat on the snow. She had promised to guide them through the crevasse fields. This was her price coming due. "The right path runs on rock under the snow," she said. "I can feel it. Cold and solid. The left is a frozen pond. By morning the sun weakens it and it opens." "You're sure," Magnus said. "I was born in the ice," she said. "It talks to me. Follow." Magnus swallowed his pride and waved them right. Winterchase led. Thornpaw ranged ahead on all fours, testing each stretch. Greta walked last, rope coiled on her shoulder, ready to haul anyone who slipped. They moved slow. They moved alive. By the time the sky turned gray, the town had shrunk to a black smudge behind them. They stood on hard, safe ground. No one had gone through the ice. Magnus pulled out his map. His half-charted line ended where the town did. He took his stub of charcoal and drew the new path, fork by fork, the way Winterchase had read it. The blank half of the chart gained one thin mark. "That's one turn," Greta said behind him. "There's a thousand more." "Then we chart them one at a time," Magnus said. He did not tell her the harder truth. Winterchase's ears kept twitching toward the smudge of the town, and her hand had not left her blade. Whoever hunted her had not turned back.

By midday the wind turned mean. It drove ice into their faces and stole the last gray light. Magnus watched his crew stumble. Frost Thornpaw dragged his paws. Greta's steps grew short and heavy. Frost Winterchase swayed on her feet, blade forgotten at her side. They had walked all night and all day with no rest. Magnus knew the truth in his gut. Push on into the dark, and someone would misstep on the ice and never rise. "We stop," Magnus said. "We build shelter here." Greta looked at the open plain. "Stop where? There's no rock, no cave. Nothing." Magnus knelt and pressed his gloved hand into the snow. It was deep and packed hard. He grinned under his frozen beard. "We don't need rock. We cut the snow itself." He pulled the short saw from his belt and sawed a block free. It held its shape, solid and square. Greta understood. She dropped to her knees beside him and clawed out blocks with her huge hands. Thornpaw shaped them with his claws. Winterchase laid her palm on each one and named the ones too soft to trust. They worked in a ring, stacking the blocks inward, leaning each course tighter than the last. The wind fought them the whole time. Twice a wall slumped and they built it again. Magnus packed loose snow into every seam. His arms burned. His crew said nothing, only cut and stacked and cut again. Slowly the dome rose. They left a low crawl hole facing away from the wind. Winterchase crawled inside first and laid both hands on the walls. "Solid," she said. "It will hold the night." They packed in shoulder to shoulder. The wind screamed outside, but inside the air went still and warm from their own breath and bodies. Magnus dug the blankets from his pack. He shook out the thick winter ones and passed them around. At the bottom sat a small quilt, sewn from a hundred bright squares. His daughter had made it for him before he left. He hesitated, then wrapped it around Winterchase's shaking shoulders. She stared at the cheerful patches, so out of place in the frozen dark. "Why give me this?" "You read the ice all night," Magnus said. "You keep us alive. Rest now." He shrugged off his heavy leather coat and draped it over Thornpaw and Greta both. One by one his crew went slack and slept. Magnus stayed awake a while, listening to the wind claw the walls that held. He pulled out his map and marked the shelter's spot with his charcoal stub. A safe camp. One more mark on the blank half of the chart. Then a sound cut through the wind. Winterchase's eyes snapped open. She sat up, quilt sliding from her shoulders, and pointed her blade at the crawl hole. "Hooves," she whispered. "On the ice. Coming this way."

The hooves faded east. Magnus pressed his ear to the crawl hole until the sound died. The riders had missed them in the storm. But the danger stayed. Come morning, he had to move the crew forward, and he had no idea where forward was safe. The dome walls hid the ice ahead. He could not chart what he could not see. Guess wrong, and they would break through hollow ice like they nearly had before. At first light he crawled out. The plain stretched white and blank in every direction. No landmarks. No solid line to follow. Greta lumbered out behind him, her red braids stiff with frost. She looked at the empty ice and crossed her huge green arms. "Which way, chief?" she said. "Or are we guessing again?" The jab stung because she was right. Last time he guessed, he almost drowned them. Magnus turned to Winterchase. The small ice elf stood wrapped in the bright quilt, her blue skin pale in the dawn. "You read the ice with your hands," he said. "But you can't feel a mile ahead. We need to see the ground before we walk it." He dug through his big leather rucksack and pulled out a coil of rope and a driven stake. An idea took shape. "Thornpaw," he called. The were-bear rose, white fur bristling, black eyes sharp. "You're the heaviest and the strongest. We tie you off and send you ahead on the rope. You test the ice with your weight. If it holds you, it holds us. If it cracks, we haul you back." Thornpaw grunted and flexed his claws. "Bait on a string," he said. But he took the rope and looped it around his chest. They drove the stake deep. Greta braced it with her bulk. Thornpaw walked out slow, testing each step, claws spread. Winterchase paced beside the rope line, one hand near the ice, calling soft warnings. "Left is thin," she said once. Thornpaw swung right. Magnus followed at a crouch, charcoal in hand, marking every safe step on his chart. The blank half of the map filled with a thin dark line. A quarter mile out, Thornpaw stopped hard. His paw broke through. Water hissed up black around his leg. "Pull!" Magnus roared. Greta heaved. The rope snapped taut and dragged the were-bear back onto solid ice. He rolled clear, soaked and steaming. Magnus knelt at the crack's edge. Beyond it the ice looked the same, but he knew now it was rotten. He drew a bold line on the map and marked the hollow with an X. Then he traced a curve around it, following where Thornpaw had held. A safe path. A real one, tested and true. He rolled the chart tight. "We go this way," he said, and pointed past the X. For the first time, he was not guessing. But Thornpaw's soaked fur was already freezing stiff, and the cold would kill him before they crossed.

The new path was tested and true, but it led nowhere Magnus could name. He knelt over his chart and traced the curve past the X. Miles of blank ice waited beyond it. No shelter marked. No supply cache. Thornpaw's soaked fur crackled with ice as he shivered. Magnus knew the truth cold in his gut. They had a safe route, but nothing at its end. Cross it, and they would freeze before finding warmth. Greta hauled the stake free and coiled the rope. "We can't march him wet across open ice," she said. She jerked her chin at Thornpaw. "He'll be a frozen carcass by noon." Magnus said nothing. He turned back to the snow shelter behind them, its thick packed walls hugging the ground. It had held through the storm. It could hold now. "We don't march yet," he said. "We get him dry first. Inside." They dragged Thornpaw into the dome. Magnus dug through his broad leather rucksack for dry cloth. His hands hit something hard and cold near the bottom. He pulled it out. A small relic, half his palm's size, worn smooth by age. He had picked it from the ice days ago and forgotten it. Now, in his grip, it changed. A faint orange glow bled through its cracks. Warmth spread into his fingers. "Winterchase," he called. The ice elf crawled close, still wrapped in the quilt. She reached for the relic, then stopped short. "That's not cold," she said, her voice low. "Nothing out here is warm. Nothing." Magnus pressed it to Thornpaw's chest. The were-bear grunted. His shivering slowed. Steam lifted off his fur as the ice melted and ran. Within the hour, his coat dried stiff no longer, but soft. The glow held steady, warming the whole dome. Greta stared at the thing. "Where did that come from?" "The ice gave it to me," Magnus said. "I didn't know what it was." He turned it over. The surface was old, older than any craft he knew. Someone had made this. Someone had walked here before, and left it behind. His pulse quickened. A warming stone in the frozen wastes meant one thing. People had survived out here. People had reached warmth. Winterchase touched the relic at last. Her pale eyes lifted to his. "These were made near heat," she said. "Real heat. Not ice." Magnus rolled his chart open again. The blank miles no longer looked empty. Somewhere ahead lay the source of this warmth. He marked a new point past the X, not a guess, but a reason to go on. "We follow the safe path," he said. "And we carry this. It buys us time on the ice." Thornpaw rose, dry and steady. Greta shouldered the rope. The relic glowed in Magnus's fist. They had a route now, and warmth to cross it. But the thing meant others had come before, and Magnus did not know if any had come back.

The relic warmed Magnus's fist, but warmth did not fill bellies. He counted the sacks at dawn and found them empty. The fuel tin held nothing but scrapings. Blank ice stretched ahead, white and flat, no shelter, no game, no end he could see. He did the math cold. Two days of walking. One day of food. His crew would starve before the ice broke into any valley. "We turn back or we die," Greta said. She dropped the last frostberry crumbs into her palm and stared at them. "There's nothing out there to eat." Winterchase knelt away from them, both hands flat on the ice. She had read the ice all night, guiding them turn by turn, and now she read it again. Her pale eyes narrowed. "Hollow," she said. "Not water. Air. A cave, under us. Wide." Magnus dropped beside her and pressed his ear to the ice. Faint, far below, he heard hooves. Many of them. "Something lives down there," he said. They found the mouth of it a half mile on, where the glacier split open. A tunnel led down into blue walls that glowed with their own light. The wind died the moment they stepped inside. Magnus's breath slowed. The chamber ran deep and still, smooth ice curving overhead like a frozen sky. At the far end grazed a herd of stocky pale horses. They lifted their heads, untamed, ears back, but they did not bolt. They fed on thick blue clumps of leaves that grew from cracks in the cave floor, layer on layer, fresh and green-blue in the dim light. Magnus had not seen a living plant in weeks. "Food," Thornpaw said. He crouched low, nose working. "Real food. And meat, if we need it." Magnus pulled a clump free and bit it. Bitter, wet, but it filled his mouth and did not sicken him. He handed clumps to the others. Greta ate three at once. Winterchase chewed slow, watching the horses, then reached out and touched the nearest one's neck. It let her. "They know the way in and out," she said. "They didn't come here to die. There's more cave beyond. Warmer air moves through it." Magnus felt it then, a thread of warm wind from deep in the glacier, the same warmth the relic held. He rolled out his chart and marked the sanctum, the leaves, the herd. Not a guess. A place that fed them. A place that pointed on. "We rest here," he said. "We eat. We fill every sack." He looked at the tunnel running deeper, where the warm air came from. "Then we follow the wind." But as the crew ate, Winterchase pressed her ear to the ice at the cave mouth. Her hand went still. "Hooves," she said. "Shod. Coming from above." The riders had found the tunnel too.

Winterchase held up one hand for silence. The riders were still above, hunting the tunnel mouth. Magnus looked at the pale horses grazing in the blue light. His crew could not outrun shod horses on foot. But the herd knew the caves. He made his choice fast. "We ride them," he said. "Deeper. Where the riders can't follow." Greta laughed once, hard. "They're wild. They'll break our necks." "Then we go slow." Magnus stepped toward the nearest mare with his palms open. She swung her head, ears flat. He stopped. He pulled a clump of blue leaves from his rucksack and held it out on a flat hand. The mare's nostrils worked. She took a step. She ate from his hand. Thornpaw moved next, low and slow, his white fur bristling. He did not lunge. He let the horses smell the bear in him and waited until they decided he was no threat. Winterchase pressed her hand to a gray stallion's neck and hummed low. The stallion stilled. One by one the herd let them close. Magnus gripped a fistful of pale mane and climbed on. The mare shuddered but held. Greta hauled her weight onto a broad-backed stallion. Thornpaw rode bareback with his claws gentle in the mane. Winterchase mounted last, light as snow. "Which way?" Greta asked. Magnus felt the warm wind on his face and pointed down the throat of the cave. He pulled the glowing relic from his rucksack. It pulsed warmer as he aimed it into the dark. "The wind and the stone agree," he said. "That way." Above, the riders reached the tunnel mouth. Iron horseshoes rang on the ice. Magnus heard shouts echo down the blue walls. "They're in," Winterchase said. "Behind us." Magnus dug his heels in. The mare surged forward. The whole herd moved as one, hooves drumming the cave floor, carrying the crew deeper into the glacier. Loose horses ran with them, a wall of pale bodies the riders could not push through. Magnus glanced back. The armed riders reined up at the herd's edge, their mounts refusing the crush of wild horses ahead. The cave narrowed. The walls dropped lower. Behind them the shouting faded, then stopped. The riders could not force their horses into the tight dark after a stampeding herd. Magnus slowed his mare when the noise died. His crew breathed hard around him in the blue glow. They had lost the riders. They had gained mounts and speed. He unrolled his chart against the mare's warm neck and marked the turn they had taken. Then he lifted the relic. Its glow burned steadier here, and the warm wind ran stronger against his beard. The passage sloped down ahead into a dark he could not see the end of. "The relic's brighter," Winterchase said quietly. "We're close to whatever made it." Magnus nodded. They rode on, toward the heat, into ground no map had ever touched.

The blue glow faded as they rode lower. The bright vegetation thinned, then stopped. The walls went dark. Magnus reined in his mare and lifted the relic, but its warm light reached only a few feet. He could not see the floor ahead. He could not see where the passage turned or fell. "Stop," he said. "All of you. Stop the horses." Greta pulled up beside him. "What is it?" "I can't see the ground." Magnus swung down and crouched. He pressed his palm to the ice and found nothing but slick dark. "One more step could drop us into a chasm. I can't chart a path I can't see." Winterchase slid off her horse and knelt. She laid both hands flat on the ice and went still. "There's a hole ahead," she said. "Wide. Ten paces on. I can feel the hollow under it." Magnus marked it on his chart by touch. But his hand shook. Feeling one hole at a time would not carry them down. They needed light. "We can't map blind," he said. "Not all the way down." Thornpaw sniffed the air and pointed one claw at the wall. Magnus followed the gesture. Low against the stone grew a carpet of soft moss. It shimmered with a pale, living glow, faint but real. He pressed his fingers into it. Cool. Bright enough to see his own hand. "It grows on the rock," Winterchase said. "On solid rock. Not on the hollow." Magnus understood. He scraped a handful of the glowing moss free and pressed it into a crack near the drop Winterchase had found. The light marked the edge. He scraped more and set clumps along the safe stone, one by one, building a lit trail his eyes could follow. The moss only grew where the ground held. Where it grew, they could step. He and Greta and Thornpaw worked down the passage, planting the glow ahead of the horses. Winterchase read the ice and called the hollows. Magnus charted each safe stone as the light revealed it. The moss ran out where the passage steepened. The dark opened below them. Then Magnus saw a red flicker far down the slope. It crackled and moved. A small beast padded up toward them, its body split with veins of molten fire. Heat rolled off it in waves. It lit the whole passage the color of a forge. Greta raised her axe. Magnus caught her arm. "Look," he said. The creature's light showed the floor clearly now, every crack and drop. It also showed the passage did not fall away. It ran down, whole and solid, toward a red glow far below. "That's the heat. That's the source." He lifted the relic. It burned hot in his hand, brighter than ever. Magnus marked the path on his chart and mounted his mare. The blind stretch was charted. The way down lay open, and something warm waited at its end.

The fire creature padded closer, and the pale horses screamed. Magnus's mare reared. She twisted under him and nearly threw him against the wall. Behind him, Greta fought her own mount. Thornpaw's horse bolted three steps and slid on the ice. Winterchase clung to her mare's neck. The heat rolled off the little lava beast, and the horses would not go near it. They pinned their ears and backed up the passage, away from the light, toward the dark and the chasm. "They won't go down," Magnus shouted. "They can smell the fire." Greta hauled her horse's head around. "Then we drive them up and go on without them." Magnus knew she was right, and it turned his stomach. The horses had carried them past the drop, past the pursuers. But no rope or blue leaf would push a horse toward flame. He swung down before his mare could throw him. "Off. All of you. We let them go." They stripped the packs fast. Thornpaw slapped the herd's flanks, and the pale horses wheeled and fled up the slope into the black, hooves ringing on the stone. The passage went quiet. Only the fire beast remained, watching them with molten eyes. Magnus shouldered his pack and lifted the relic. It burned hot against his glove. "On foot, then. We follow the light." The little beast turned and started down, and they followed it, one careful step at a time, over the solid rock its glow revealed. The passage opened. Heat struck Magnus's face like an open oven. Before them lay a pool of molten stone, ringed with rough black rock. Its surface turned slow and red. The fire beast trotted to the rim and stopped. Someone stood at the pool's edge. Small, slender, blue-grey skin marked with lines of gold that glowed like the moss. A crystal at its brow caught the molten light. It clasped its hands and would not meet their eyes. The fire beast pressed against its leg like a dog come home. Greta raised her axe. Magnus caught her arm again. "Wait," he said. He set the relic on the stone between them and the small one. Its glow leapt up bright, answering the pool. The shy creature looked at the relic, then at Magnus. Its shoulders eased. "You made this," Magnus said. He touched the relic. "Or your people did. You live by the heat." The creature gave the smallest nod. It lifted one hand and pointed past the molten pool, to a low arch in the rock where warm air moved. Magnus drew his chart and marked the pool, the arch, the way through. The horses were gone. The road behind them was blocked with dark and stone. But the warmth he had chased across the whole frozen waste stood in front of him now, and a living thing had pointed him toward its heart.

Magnus knelt at the pool's edge and pointed at the low arch. The blue-grey creature watched his hand. He tapped the warm passage, then spread his arms wide, a question. Did the road reach the valley, or die in the rock? The creature only blinked. It did not understand his words, and he did not know its tongue. "Ask it plainer," Greta said. She still gripped her axe, but low now. "We don't cross a hundred miles on a shrug." Magnus drew his chart. He traced the mapped route with one finger, then held the paper out. The creature leaned close. Its gold lines brightened. It touched the ink, then shook its small head and drew back. Magnus's stomach sank. The gesture could mean the way was blocked. It could mean nothing at all. He had no way to know. He tried once more. He lifted the relic and set it on his chart. "You made this. You know the heat. Show me where it goes." The creature stared at the glowing stone. Something in its face changed. It stepped to a shelf of black rock and lifted a small object. It was a compass. Gold ringed its face, worn thin at the edges. Strange marks circled the dial. The needle was not iron but light, pale blue, and it swung on its own. The creature pressed the compass into Magnus's palm and closed his fingers over it. Then it pointed at the warm arch, then at the compass, then at the arch again. Magnus turned the compass flat. The needle spun, steadied, and pointed straight through the low arch. He shifted his feet. The needle held its line. He walked three steps toward the molten pool, and it swung to keep the arch. The thing did not seek north. It sought the heat ahead, the source, the far warm place. "It's giving us a guide," Winterchase said. She crouched beside him, her voice low. "A true one. Not a guess." Magnus looked at the creature. He touched his chest, then the compass, then the arch, and gave a slow nod of thanks. The creature clasped its hands and stepped back into the pool's red glow. The fire beast curled at its feet. It would not follow. This was as far as it walked. Magnus rose. He marked the compass on his chart, then the arch, then wrote one word beside them: TRUE. For ten chapters he had read the ice one blind turn at a time. Now the pale needle pointed the road for him. "Through the arch," he said. "We follow the needle." He stepped into the warm passage. The needle held steady ahead. But the air past the arch was not still. It moved against his face in slow, steady pulses, like something far down was breathing. The compass showed the way. It did not show what waited at the end of it.

The warm passage narrowed as they walked. Magnus watched the pale needle hold its line ahead. But Greta lagged behind him now, and Winterchase's steps had gone slow and heavy. He knew the reason. Their packs were near empty. The blue vegetation that had fed them was gone, left behind in the cold caves. No such food grew in this hot rock. He counted the last handful of leaves in his palm and knew it would not last one more day. "We can't chase the needle on empty bellies," Greta said. She leaned her axe against the wall and sat. The troll's broad shoulders sagged. "Find us food, Magnus, or find us a grave." Magnus said nothing. He tucked the compass in his coat and studied the passage. Warm air pulsed against his face. Then he heard it, a soft chorus of squeaks from a crack in the rock. He knelt and looked. In a shallow hollow, warmed by the stone, sat a heap of small round creatures. They were plump and orange, dappled with green spots, and they blinked up at him without fear. "Murmlets," Winterchase said. She crouched beside him. Her voice lifted for the first time in hours. "Ice elves know them. They breed in warm pockets. They're safe to eat." Magnus reached in slow. The nearest creature let him lift it. It fit both his hands and did not squirm. "There's dozens," he said. "Maybe more, deeper in the crack." Greta was already up. She pulled a wide net from her pack and spread it at the hollow's mouth. Winterchase reached into the warm gaps and coaxed the creatures out. They came in a soft, tumbling flood, squeaking, rolling over one another. Magnus caught them by the armful and passed them back. Greta filled the net, then a sack, then a second sack. They built a small fire from the fire creature's cast-off embers gathered in a tin. Magnus turned the murmlets over the coals. The smell filled the passage, rich and good. They ate until the ache left their bellies. Greta ate six and laughed for the first time in days. Magnus packed the rest, salted from his dwindling pouch, wrapped tight for the road. He counted the load. Four days of food, maybe five. He marked the hollow on his chart, then wrote beside it: MURMLETS, WARM POCKETS. He drew the compass out again. The pale needle swung and held, pointing deep into the hot dark ahead. His crew stood behind him, fed and standing straight. But the warm air still pulsed against his face in slow, steady beats, stronger now than before. Something large lay ahead, and it was breathing. Magnus tightened his pack straps. "We eat as we go," he said. "Now we find what's making that wind."

The passage climbed for three days. Magnus followed the pale needle up through hot rock, then cool rock, then rock that grew cold. The warm wind died behind them. His crew ate the last murmlets on the second day. On the third, Greta scraped her sack empty and held it upside down. Nothing fell out. Magnus stopped and drew the compass from his coat. The needle held its line, aimed up and ahead. But it told him nothing he needed most. He knew the heat lay that way. He did not know how far. "We ration for what?" Greta asked. "Two days? Ten? You're guessing, Magnus." He was. A wrong guess meant they starved a mile from warmth, or stuffed their bellies now and dropped dead a week short. He turned the compass in his hands. The luminous face glowed faint in the tunnel gloom. He watched the needle and remembered the molten pool far below. Down there the needle had swung wild and bright. Higher up, it had steadied. He tapped the glass. The needle barely trembled. "The glow," he said. "When we were close to the fire, the whole face burned. Look at it now." He held it up. The light was thin, almost gone. "It's dim because the heat's far. When we near it, the face will brighten. The compass tells distance too. We just weren't reading it." Winterchase leaned in. She pressed one palm to the cold wall, then to the compass glass. "The rock's near freezing here," she said. "Days from any heat. Your face agrees. When it flares, we're close." Magnus made the call. He split the food thin, one strip of dried murmlet each, and packed the rest deep in his broad rucksack. "We eat like this until the compass burns bright," he said. "Then we eat full and push hard the last stretch." Greta grunted but took her strip and chewed it slow. They climbed two more days on the ration. The needle held. The face stayed dim. On the third morning the tunnel mouth opened above them, a ragged hole of gray light. Magnus pulled himself out and stood. Ice. Flat white ice ran to every horizon. Wind cut his beard. They had crossed under the glacier and come up on its far side, into open waste again. No valley. No warmth. Just cold and sky. Magnus's chest tightened. Then he drew the compass. Its face blazed gold in his hand, bright as it had been at the molten pool. The needle stabbed across the ice toward a low white ridge in the distance. "There," he said. His voice shook. "It's close. Half a day, no more." He turned to his crew. "Eat," he said, and opened the rucksack wide. "All of it. We finish this today." They ate on the ice while the compass burned in Magnus's fist, pointing at the ridge.

The food gave them strength for one hard march. Magnus led his crew across the ice toward the white ridge, the compass burning gold in his fist. Then the ground broke open. A crack split the ice before them, wide as a wagon. Magnus stopped at its lip and looked down. Black water or black shadow. He could not tell. On the far side lay a low white shelf, and beyond it the ridge that held the warmth. "Can you read it?" Magnus asked. Winterchase knelt and pressed both palms flat to the ice. She closed her eyes. Her fingers moved along the edge, then stopped. "The far side is water under thin crust," she said. "Not rock. If you step there, you fall through." She opened her eyes. "Half a day's warmth, and a river we cannot cross." Magnus walked the crack's edge. It ran left and right until it vanished into gray haze. Too far to go around. Greta thumped her heavy fist against the ice. "Then we swim, or we die here in sight of it," she said. Magnus shook his head. Wet clothes in this wind meant death. A snort stopped him. Across the crack, a horse stood on the thin white shelf. It was stocky and broad, its coat dark blue shot through with purple. It watched them with steady eyes and did not sink. On its flank clung a small marmoset, its fur frosted white, its wide eyes fixed on Magnus. The horse pawed the crust. It held. "It stands where you say we'd fall," Magnus told Winterchase. She frowned. "Then the crust holds a light weight in one place and not another. It knows the ice. We don't." Magnus watched the horse cross the shelf. Its hooves found firm spots the eye could not see. He made his plan. "We follow it," he said. "Not straight. Where it steps, we step." He unwound the rope from his pack. He tied one end to Greta, the strongest, and the other to himself. Winterchase would read each step before he took it. The horse turned along the crack. It walked a slow line, and where its hooves pressed, the crust rang solid. Magnus followed, one boot at a time, testing with the rope taut behind him. Winterchase called out the soft spots. Greta braced to haul him back. The marmoset chittered from the horse's back, and the horse kept moving. The line the horse walked was not a bridge, but it held like one, a hard span of clear ice bending toward the far shelf. Magnus crossed it step by step. His crew came behind, roped and slow. When his boots touched the white shelf, it did not give. He turned and pulled Winterchase up, then Greta. The horse trotted ahead toward the ridge and did not stop. Magnus stood on solid ground at last. Between him and the warmth lay no more water. Only the climb.

The white ridge rose ahead, a wall of ice between Magnus and the warmth. He counted the murmlets in his pack. Two days of food, maybe three. He could not see past the ridge. He did not know if a man could climb it. Guess wrong, and they would starve on the wrong side of the world. "We find the route before we spend the food," Magnus said. "Not after." Greta grunted and shouldered the coil of rope. Winterchase pressed her palm to the ridge's base and shook her head. "Solid rock under the ice here," she said. "But I cannot feel the top. Too high." Magnus walked the base and looked up. The face ran smooth and steep. No ledge, no crack he could reach. Then he saw the trees. A cluster of slender trunks grew from a shelf halfway up, their branches glazed white and shining. Roots meant cracks. Cracks meant handholds. "There," he said. "If we reach those trees, we can see the far side." The blue horse stood higher up, on a narrow ledge Magnus had not marked. The frosted marmoset clung to its flank and chittered down at him. The horse pawed the ledge, then climbed a slanted seam in the rock, slow and sure. Magnus watched where its hooves found purchase. He traced the line with his eyes and fixed it in his mind like a route on a chart. "We follow the horse again," Magnus said. He tied the rope to Greta, then to himself. Winterchase went first, reading each hold before he trusted it. Her fingers found solid rock where the eye saw only ice. Magnus climbed after her, boots wedged in the seam the horse had shown. Greta braced below, ready to haul. The wind tore at them. Magnus's beard froze stiff. Near the frost-glazed trees, his boot slipped on glass ice. He dropped. The rope snapped tight and Greta held him. He hung, swung, then caught the trunk of a frozen tree and pulled himself onto the shelf. His hands bled through his gloves. He stood among the shining branches and looked over the ridge. Below spread a bowl of green. Winterberry bushes grew thick with red fruit. A stream ran dark and unfrozen. No snow lay in the hollow at all. The warm valley. It was real, and it was close. An ice butterfly the size of a hawk lifted from the trees below. Its wings shimmered with frost, and a crown of ice rose from its head. It circled the valley once, then settled on a winterberry bush and folded its great wings. Magnus watched it and did not know if it guarded the place or lived in it. "I can see the route down," Magnus called to his crew. "The valley is there. We can eat when we reach it." He marked the descent in his mind and started back for the rope. The climb into the valley would be the next thing, and its guardian waited below.

Magnus climbed back down to his crew and led them along the descent he had marked. The route dropped through frost-glazed trees into the green bowl. He kept his eyes on the great ice butterfly below. It sat on a winterberry bush, wings folded, crown catching the light. He did not know if it would strike when they reached the floor. He tightened his grip on his staff and stepped down first. The air warmed as they descended. Magnus's beard thawed and dripped. Greta came behind, one hand on the rope, watching the butterfly. Winterchase pressed her palm to the rock and frowned. "It has not moved," she said. "It knows we are here. It waits." They reached the valley floor. Grass bent under Magnus's boots. The butterfly lifted from the bush and rose into the air. Its wings threw cold light across the hollow. Magnus stopped and raised his empty hand. "We only want to pass," he said. "We came far. We are hungry." He did not reach for his staff. He held still and let the creature choose. The butterfly circled him once. Its wings brushed the air near his face, and he felt no attack, only cold breath. Then it drifted to the stream and settled on the water's edge. It dipped its crown to drink. Magnus let out his breath. It had let them pass. The valley woke around them. Small mice with bright wings darted from the grass and chased each other between the bushes. A cluster of glowing bats hung under a frosted branch, their wings soft with blue light. A blue-furred dog with delicate wings trotted from the reeds and sniffed Greta's boot. She knelt and let it press its nose to her palm. "They are not afraid of us," she said. "Nothing here has learned to run." Magnus walked to the winterberry bushes. He picked the red fruit and ate. It was sweet and full of juice. His crew ate beside him, saying nothing, filling their hands. Bees of clear ice drifted among the flowers, their frosted wings sparkling. Across the stream, a great elk raised its head. Ice horns branched from its skull, and pale scales ran along its flank. It watched the strangers, then bent again to graze. Magnus sat on the warm grass and pulled out his chart. He had drawn every step from the tavern to this bowl. He looked at the blank space beyond the valley's far rim, where the green ended and the map ran out. The warm valley was real. He had found its heart and lived. But the far side he had not yet seen. Winterchase sat beside him. She looked back the way they had come, toward the ridge and the ice beyond. "They are still out there," she said. "The ones who follow me." Magnus marked the valley on his chart and did not answer. He had reached the warmth. Now he had to hold it.