Coquina had four hours of skin left before she cracked, and the market wharf wouldn't look at her. She sat on the crate they'd given her out of pity, tail hidden under a wet burlap sack, and watched the reef folk pretend she wasn't there. Two days ago the coral had gone quiet in the night. That was how she'd known the pearl was gone. Without it, the reef she called home would bleach white inside a week. The elder fisherman had held that pearl last, the same man who'd been lifting shells and sea-glass and worse from her water for twenty years while every person on this dock looked the other way. She'd already asked the netmender. She'd already asked the woman who sold ice. Both had shrugged and turned back to their work. Now she tried the tea seller under the pastel awning, a plump woman arranging a hanging basket of pink lilies and trailing charms above her doorway. "He took it inland," Coquina said. "That's all I need. Which road." The tea seller adjusted a ribbon on the basket. "I don't know any fisherman." "You've bought from him. Everyone here has." The woman's hands paused. Then she went back to the ribbon. Coquina slid off the crate. Her tail hit the boards hard. Heads turned along the wharf and then, one by one, turned away. A man coiling rope stepped inside his shed. A boy carrying oysters walked faster. The silence wasn't accident. They were closing around the fisherman the way they always had, and her clock was bleeding out under the sun. She dragged herself to the middle of the wharf where they all had to see her. She pulled the burlap off her tail. Scales flashed green and pink in the light. A woman gasped. A child pointed. Coquina lifted her voice so the whole dock heard. "My reef dies this week. You've all eaten off it. Look at me and say you didn't." No one answered. But a girl at the edge of the crowd, maybe ten years old, tugged at an old man's sleeve and whispered something. The old man cuffed her hand down. The girl caught Coquina's eye and mouthed two words: back room. Then she pointed, quick, at the tea seller's shop. The tea seller had gone white. Coquina hauled herself across the boards toward the pastel doorway. The tea seller stepped in front of the door. "You can't. He'll—" "He'll what." Coquina looked up at her. "He's not here. You are." The woman didn't move. Coquina shoved past her tail-first and pushed the door open. Inside, past a small swing hung with cherry blossoms and pearl-strung ribbons, a ledger lay open on a table. Names. Dates. A shipment address three days upriver, marked for a buyer at a shell-white castle she had heard of only in stories. She had her road. She also had three hours of skin, a village that now knew her face, and a fisherman who would hear she was coming before nightfall.

Coquina had the address, but the address sat three days upriver. She could not walk it. She could not swim it either. River water was fresh, and fresh water burned her gills. Her salt was already thinning. Two hours of skin left, maybe less. She sat behind the tea seller's shop and stared at the brown current sliding past the pilings. The pearl moved farther from her every hour, and she had no way to follow. The back door creaked. The young girl from the crowd slipped out. She carried a wet bundle in her arms and a small round creature perched on her shoulder. The creature was a bear cub, pale pink and blue, its fur catching light like frost. It blinked at Coquina with huge eyes. The girl set the bundle down. "You can't swim the river," the girl said. "I heard you say it inside." She pulled a cloth off the bundle. Underneath sat a wide clay jar packed with dark green weed and gray silt. "Reef mud. And bloodwort. My grandmother packs gills with it when she moves live fish upriver. It holds the salt in. Keeps them wet inside." Coquina touched the mud. It was cool and thick. "How long does it last?" "A day. Maybe more if you stay under." The girl looked back at the shop. "He's coming. The fisherman. Someone rode ahead to warn him. You have to go now." Coquina packed the mud into her gills with both hands. It stung, then steadied. The burn eased. She could feel the salt hold, sealed under the silt like a wet second skin. She lowered herself off the pilings into the cold brown water. Her tail found the current. The gills pulled, and for the first time the fresh water did not tear at her. The bear cub leaped from the girl's shoulder and landed on Coquina's back. It gripped her hair and would not let go. "He won't stay behind," the girl said. "He likes you. Take him. He'll warn you if anything follows." Coquina looked up at the girl one last time. "Why help me?" "Because they won't." The girl pointed past the wharf, upstream, where the water narrowed toward the hills. "The white castle is up that way. Follow the deep channel. Don't surface near the boats." Coquina pushed off the piling. The current took her. The cub pressed flat against her spine, warm and shaking, its small claws hooked in her hair. Behind her the wharf shrank. She swam into the fresh water and did not dry out. But the girl's warning stayed with her. The fisherman knew she was coming. He had a head start and a boat. She had a day of borrowed salt, a stolen route, and a bear cub who could not talk. Somewhere upriver the shell-white castle waited, and the man who took her pearl would reach it first.

The channel narrowed here. The brown water grew clear over pale stones. Coquina swam low, gills sealed with mud, the cub flat against her back. She was gaining on the fisherman. She could feel it. Then the cub's claws dug into her hair. It made a small sharp sound and stared ahead. She stopped and looked. Across the deep channel hung a net. Fine dark rope, weighted low, stretched from bank to bank. Pale flowers dotted the water above it, wide blooms with pearl-speckled petals floating on the surface. They looked harmless. But under them the net waited, and hooks glinted along its edge like teeth. The fisherman had left it to catch her. If she hit it, she was done. He would reach the castle while she tangled and drowned in fresh water. She hovered, breathing slow. The net blocked the only deep path. Above it the water turned shallow and warm, too thin to hide in. She had no way through and no time to find one. "Don't touch the flowers." The voice came from the shadow of the far bank. A mermaid rose from the reeds. His tail shone in soft pastel scales. Blonde dreadlocks hung wet down his back. Blue eyes fixed on the net, not on her. Coquina pulled the cub tight and backed away. "The blooms mark the trip line," he said. "Brush one, the net closes." He swam nearer, calm, keeping low. "He set it wrong, though. Left a gap." "Who are you?" "Cove." He pointed at the net's far corner, near a sunken ledge. "There. The weight slipped off that stone. The hooks ride high. You can pass under." She stared at the gap. It was narrow. One wrong beat of her tail and the hooks would find her. "Why help me?" "You're chasing him." His voice dropped, quiet and flat. "So am I, in a way. He's why I know this water." He looked at her then. "Go slow. Keep your tail down. I'll hold the line off you." Coquina lowered herself to the stones. Cove gripped the net's edge and pulled it taut, away from the gap. The hooks lifted. She slid forward on her belly, the cub pressed flat, her mud-packed gills scraping the ledge. A hook grazed her fin. She held still, then eased past. The gap opened. She swam clear on the far side. Cove let the net fall. It snapped shut behind them with a wet crack. The flowers scattered. He surfaced beside her upstream, breathing hard. "He's half a day ahead. No more." Coquina looked at the closed trap, then at the mermaid who knew every stone of this river. Her only chance had not been lost. It had grown a guide. "Then we don't stop," she said. The cub chirped. The three of them pushed on into the clear deep channel, toward the shell-white castle.

The channel opened wide near dusk. Ahead, the shell-white castle rose from the bank. Its walls dropped straight into the river. Coquina slowed. She saw no gate, no low door, only smooth stone and dark water beneath it. Guards moved along the top. She could not swim in blind. If they spotted her, the fisherman would hand off the pearl and vanish. The cub gripped her hair and made a small sound. "Stop here," Cove said. He pointed to a bed of tall flowers along the shallows. Pink blooms speckled with pearl-white dots floated among the reeds. "We watch first. We don't rush a place we can't see into." Coquina pushed into the flowers and went still. She hated waiting. Every hour was salt she did not have. But charging the wall meant capture. She watched. The guards passed, turned, passed again. Then she saw it. A pale shape slipped from a crack low in the wall, right at the waterline. A dolphin. Small, silver, dotted with tiny shells. Pearls ringed its tail. It nosed the flowers, curious, then looked at her with wide dark eyes. Coquina held her breath. The cub chirped. The dolphin chirped back and swam a slow circle, close, unafraid. "It came from inside," Cove said, low. "There's a way through that wall. Under the water." Coquina followed the dolphin's path with her eyes. It had come from the crack, swum out, and now turned back toward it. The gap sat below the guards' sight, hidden by the flower bed. A drain, or an old flooded passage. Wide enough for a body. "They can't see the base from up there," she whispered. "The flowers hide it." Cove nodded. "Then that's our door." They moved when the guards turned. The dolphin led, quick and sure, weaving through stems. Coquina swam behind it with the cub flat on her back. The crack yawned dark ahead. She pressed her mud-sealed gills tight and slid in. Cold stone scraped her shoulders. The passage bent, then dropped. She kicked hard and came up inside. Water lapped in a stone room within the castle. Faint light fell from a grate above. A bench sat against the far wall, dry and grand, carved with entwined flowers and pale pearl beads and a wide shell for its back. This was no dungeon. This was some private garden room, and the fisherman had come through here. She was sure of it. Cove surfaced beside her, silent. The dolphin circled once and dove back out. The cub shook water from its ears. "We're inside," Coquina said. Her voice shook. "Now we find him." Then a voice called out above the grate. Boots crossed stone. A second voice answered, closer. They knew someone had come through the wall. The way out behind her led back to open river and drying gills. Ahead lay the castle, the fisherman, and men now looking for her.

The boots came closer above the grate. Coquina pressed her back to the stone wall. The cub clung to her hair and shook. She scanned the garden room for a door, a shadow, anything. There was only the grand bench, the water at her tail, and no place to hide. In minutes the guards would climb down and find her. "We can't fight them," Cove whispered. He gripped the bench edge and looked at the water. "And we can't outrun the whole castle." Coquina's chest tightened. Her gills burned under the drying mud. She had crossed a river and a net trap to get here, and now a stone room would end it. Then the dark water rippled. A pale head rose, silver, dotted with tiny shells, pearls ringed around its tail. The dolphin had followed them in. It chirped and dove, then rose again by the far wall. Coquina swam to it. Below the surface, a low arch opened into shadow. Another flooded passage, hidden under the water line, leading deeper into the castle. "It's showing us a way out," Coquina said. "Away from the grate." Cove hesitated. "We don't know where it goes." "We know where staying goes." She pulled the cub tight and slid under. Cove followed. The dolphin swam ahead, sure and quick through the black. The passage bent twice, then brightened. Coquina came up in a wide pool. Soft pastel light fell over pale flowers and arching shells. Pearl-white blooms glowed along the walls. It was a garden built inside the castle, quiet and empty, far from the search. She had swum past the fisherman's men, not through them. But the light was not the only glow. On the pool's far edge floated a small figure with curling clear wings and a shell-scale dress. A fairy. She sat on a lily pad, arms crossed, foot tapping. "There you are," the fairy said. Her voice was bright but sharp. "I have been searching this whole castle. Do you know how many guards I flew past?" Coquina's throat closed. "Pearl." Pearl Shellwater flew to her and gripped her face in tiny hands. Her wings blurred. "You left without me. Again. I follow a bear cub and a dolphin halfway upriver, and I find you half dry and hiding." Her eyes filled. "Never do that again." "I didn't want you hurt," Coquina said. "You need me." Pearl wiped her eyes and pointed past the flowers. "There's a room through that arch. Locked. Two guards outside it. And I heard the old man's voice inside." Coquina's breath caught. The fisherman. The pearl. Both close, behind a locked door and two guards. The dolphin circled the pool. The cub chirped. Coquina was no longer trapped. She was one door away. "Then we get through that door," she said.

Coquina swam to the arch and pressed her hands to the door. It was thick wood, banded with iron, locked tight. She had nothing to break it. Beyond it lay the fisherman and the pearl. Boots scraped somewhere behind the flowers. The guards were sweeping closer. She had minutes, maybe less. "Push all you want," Pearl said, hovering near the lock. "It won't move. I already tried the keyhole. Too small even for me." Cove ran his palm along the door frame. "Solid. We can't force it." He looked at the water. "And we can't stay." Coquina's gills burned under the drying mud. She scanned the garden pool. The dolphin circled below, shells and pearls bright along its back. It chirped and nudged the wall beside the door, then again, harder. Coquina watched the stone there. A seam ran through it, thin and dark, where water seeped from the pool. "There," she said. "The wall's cracked, not the door." She pushed the fisherman from her mind and pressed both hands to the wet stone. It shifted. Just barely. "Cove. Help me." He set his shoulder beside hers. The dolphin rammed the seam from below. Pearl darted to the top edge and pulled with all her tiny strength. "On three," Coquina said. "One. Two. Three." They shoved together. Stone ground against stone. Water poured through the widening gap. A slab tilted inward and crashed down into a dim room. Dust and pool water rushed after it. Coquina hauled herself through the broken wall. She landed on a wet floor. Shelves lined the room, crowded with reef things stolen over years—coral, shells, and one small stand at the center. On it sat the pearl. It glowed soft and white, the same light she had felt go silent in her reef. But the room was empty. No fisherman. A door on the far side stood open. Beyond it, a hall stretched toward pastel windows and rows of shimmering tails on display. She heard the old man's voice, close, giving orders. Then a woman answered him—calm, sharp, used to being obeyed. Pearl flew in and gasped. "He heard the wall. He ran." Coquina grabbed the pearl and held it to her chest. Its warmth spread through her hands. She had it. After the river, the net, the guards, she finally had it. Then boots pounded in the hall. The fisherman shouted for the guards to seal the shop. Through the far door, Coquina saw the woman step into view. A mermaid with flower-crowned hair moved among the hanging tails, her face turning toward the noise. She ran this place. And the fisherman was standing at her side, pointing back at Coquina. "We have to go," Cove said. Coquina looked at the broken wall behind her, then the open door ahead. The pearl was in her hands. But the only way out led straight through the fisherman and the woman who protected him.

Coquina held the pearl tight and swam through the open door. The hall opened into a bright shop. Shimmering tails hung in rows along the walls. Delicate jewelry glinted on shell stands. A cherry tree stood in the center, its branches strung with pearls and small bubbles. The fisherman crouched behind it. And the flower-crowned mermaid stood between Coquina and the far exit, her tail bright with scales. This was the woman who ran the whole operation. The one who protected the fisherman. The one who let the pearl be stolen while Coquina's reef went silent. Coquina's chest went hot with anger. "You took what keeps my coral alive," she said. "I'm leaving with it." The mermaid didn't move. Flowers crowned her purple hair, and her blue eyes flicked from Coquina to the glowing pearl. "He said you'd come," she said. Her voice was calm, but her hands stayed still at her sides. "He said you were a thief." "He's the thief," Coquina said. She lifted the pearl. Its white light spread across the mermaid's face and lit the hanging tails. "This came from a living reef. Your shop sells dead reef things. Coral. Shells. Now this." The fisherman stood. "Take it back from her, Marina. She broke in. Call the guards." But Marina's eyes stayed on the pearl. Something shifted in her face. She looked at the shelves of stolen reef things, then at the old man. "You told me these came from empty reefs," she said. "You told me nothing died." "They didn't," he said, too fast. Coquina heard the lie in it, and so did Marina. The mermaid's jaw tightened. She looked at Coquina again, at the burning gills under her mud, at the pearl she clutched like her own heart. "Go," Marina said. She swam aside and cleared the path to the exit. "Take it. Before I change my mind." The fisherman shouted and lunged. Pearl darted from behind the tree and yanked a strand of hanging beads loose. It swung down across his path. He caught his arm in it and tumbled into the pool below the cherry tree. "Now, Coquina!" Pearl cried. Coquina swam hard for the exit. Cove was already there, holding the way open. She shot through into cool water, the pearl warm against her chest, Pearl and the cub close behind. Behind them Marina blocked the fisherman, her arms crossed, guarding the door she had just opened. The old man screamed for guards. But the guards answered to her, and she said nothing. Coquina broke into open river beyond the castle wall. The pearl glowed steady in her hands. She had it, and no one chased her now. But the water ahead was still fresh, her salt still thinning under the mud, and her reef lay a long swim downstream.