Mary Rose Morris kept the iron arrow across her knees and watched the door of her cottage. Somewhere past the rose trees, at a revel she had not been invited to, a faerie was dancing in her brother's face. She had seen it twice now. The first time she nearly ran to him. The second time she nearly shot him. She could not tell the thief from the boy, and that was the whole problem. The cottage smelled of thatch and old smoke. Her brother's coat still hung on the peg by the blue door. He had walked out wearing it a month ago and had not come back. What came back wore his mouth and did not know how he took his tea. She turned the arrow in her hands. A traveling smith had made it for a bag of silver and a promise. Runes ran down the iron head. He swore it would bite only the shapeshifter, and pass through her brother like wind. She did not fully believe him. Belief was not the same as certainty, and certainty was what she needed before she drew the bow. She needed a way to see through the glamour. She needed it tonight. Mary Rose pulled on her boots and stepped out among the dark rose trees. Thorns caught her sleeve. Past the last hedge, the black dragon lay curled in the meadow where it had slept since she was ten. It opened one yellow eye when she approached. "I need the library," she said. "The one across the ridge. Tonight." The dragon lowered its shoulder. She climbed on. They landed at the stone steps of the faerie library before the moon cleared the towers. Ivy crawled the walls. Every window burned with candlelight. Inside, the shelves went up three stories and smelled of dust and cold apples. She walked the aisles until she found the section she wanted: records of faeries who had worn stolen faces. She read standing up. She read for hours. Most of the accounts ended in a funeral. One did not. A hedge-witch two hundred years ago had brewed a tea from black rose petals and iron shavings. One sip, she wrote, and the drinker's eyes saw through any borrowed skin for a single night. Mary Rose copied the recipe onto the inside of her wrist. Her hands shook. She had thorns in her garden and iron on her arrow. She could brew it by dawn. She was halfway down the library steps when she saw the figure waiting at the bottom. Her brother's coat. Her brother's smile. He lifted one hand in greeting. "You've been gone a long time," he said. "Come home." He did not know she now had a way to be sure. She kept her face still and started down the steps.

Mary Rose walked down the library steps with the recipe still wet on her wrist. The thing wearing her brother's face waited at the bottom, hand out, smile ready. She took the hand. It was warm. That was the worst part. She let the dragon carry them both home under a thinning sky. At the cottage door, he shrugged off the black coat and hung it on the peg. His shaved head caught the lamplight. The tattoos on his neck crawled when he swallowed. He watched her the way her brother never had, tracking every move of her hands. "You're up late," he said. "Making something?" "Tea," she said. "For my headache." She could not brew it in front of him. The iron shavings alone would tell him what she was. He would bolt, or he would put a knife in her back before the kettle sang. She needed him out of the cottage, or she needed a wall he could not see through. She thought of the root cellar. Thick door. Stone walls. And bolted to the inside of that door, the old iron panel her father had hammered up against faerie mischief years ago. Iron on iron. No glamour could listen through it. "I left my basket at the ridge," she said. "Black roses. I need them for the tea. Would you fetch them? My legs are done." He hesitated. His eyes flicked to her wrist. She pulled her sleeve down. "Please," she said. "Before dawn. They wilt." He nodded once and took the coat back off the peg. The blue door shut behind him. She moved fast. She grabbed the black petal roses already hidden in the flour bin, the twist of iron shavings from the arrowsmith's pouch, and the small iron cauldron from the hearth. She carried it all down into the cellar and dropped the bar across the door. The iron panel hummed cold against her palm. She struck flint. The cauldron caught. Water, petals, shavings. The brew went black as a wet crow. It smelled of rust and rot. She counted to sixty, then poured a cup and drank. Her eyes burned. The cellar sharpened. She could see the grain in the wood, the veins in her own hand. Footsteps crossed the floor above her. The blue door had opened. He was back too soon. He had not gone to the ridge at all. "Sister?" he called. His voice came down through the boards, close to the trapdoor. "Where'd you go?" She held the empty cup. The tea sat hot in her chest. She had it. She had one night of true sight, and the shapeshifter was already standing over her head, sniffing for the smell of iron. She picked up the arrow.