Danu knelt at the black water and knew it was sick. She was the old mother, Anu, who had named the rivers before her children learned to speak. She had come to the bog to birth a new god from its deep currents, a heir to hold the land after she was gone. But the water under her palm was wrong. Something older than her was pulling at the roots, and now a second poison had struck it from above. Florence stood behind her, barefoot in the reeds, yellow dress muddied to the knee. The witch had broken her own salt circle to call for help, and her hands still shook from it. "He is at the tower," Florence said. "Something is hurting him. The water tastes like it too." Danu rose. "I feel it. The same wound in both." "Then I'll go—" "No." Danu set a hand on the girl's shoulder. "Sit. Breathe. You gave the water spirits a piece of yourself to keep him. Do not spend more tonight." Florence's mouth opened, then closed. She sat. Danu walked to the little drying shed behind the hut. Bundles of St. John's wort hung in tidy rows, gold blossoms still bright. She pulled down three bundles and crushed them between her palms. She waded into the bog to her thighs and let the crushed flowers fall. The water swallowed them. A slow pale light spread out from her legs. "Isa," she said to the dark. "Wake up. I need the low notes." Far off, in the arbor where the piano slept, a chord struck itself. The bog carried it. The pale light in the water steadied and began to clean. But the poison at the source was still bleeding in. Danu turned toward the tower rising past the trees, its telescope tilted at the sky. She found the fairy on the stone steps, wings folded, watching Hozier where he slumped against the base. He was gray as wet peat, breathing shallow. Moss clung to his jaw. "Stop," Danu said. The Leanan Sidhe looked up. "Mother. You came down for a musician." "I came down for the water you are spoiling." Danu stepped between them. "You do not drain them out of spite. Listen to me. You carry a cracked piece of our old fire. My fire. A mortal heart cannot hold a god's weight without burning to ash. That is what you do to them. That is all you have ever done." The fairy's mouth thinned. "A pretty story." "It is the true one. My children went under the hills and were forgotten and became your kind. You are what is left of us." The Leanan Sidhe stared. Then she stepped back off Hozier. The pull on the water eased. Danu felt the deep currents run clean again under her feet. Hozier coughed once and opened his eyes. "Florence," he said. "She is safe," Danu answered. "Now stand. The bog is ready to give me a child, and I need you both to witness it."

Danu left Hozier at the base of the tower and walked back toward the water. She could feel it before she saw it. The fairy had drained the shadow-horse dry and left the husk in the reeds, and now a black slick was crawling out of that spilled corruption. It moved slow but sure, downhill, toward the deep pool she had chosen for the birth. If it touched those waters first, her child would come up wrong. She had cleaned the poison from above. She had not planned for the poison below. She looked at the slick and knew she could not simply burn it. It was old fire, her fire, curdled. Fighting it would only splash it further. It had to be taken in and held by something that could carry it without breaking. She needed the bog man. And she needed the one who kept him standing. She found the cottage past the cherry trees, its roof green with living moss, a weather-vane raven turning on the spire. Hozier was already at the door, pale hand raised to knock. He had come on his own. He always knew when he was needed. The door opened before he touched it. The tall man inside wore a dark feathered wrap and held a yew-wood bass by the neck. Alex was Hozier's soul friend, the steady beat under the storm, the reason Hozier had not come apart on the first night out of the peat. He looked at Danu once and stepped aside. "Mother," Alex said. "I need him to take the sickness into himself," Danu said. "All of it. Before it reaches the pool." Alex's jaw tightened. "That will hurt him." "Yes." Hozier spoke from the doorway. "I'll do it." "You don't know what she's asking," Alex said. "I know the bog," Hozier said. "It kept me. I owe it." Alex looked at him a long moment. Then he lifted the bass. "I'll hold you to the ground. Don't drift." They walked out together. Danu led them to the slick's leading edge. Hozier stepped into it barefoot. The black climbed his shins like ink up cloth. He did not flinch. Alex sat on a stone at the bank and set his thumb to the low string. One note. Then another. The hum went into the peat and stayed. Hozier waded deeper. The slick chased him now, pulled toward him, hungry for a body that could hold it. His skin darkened. Moss on his jaw went black. He kept walking until the last of the corruption left the ground and was inside him. The birthing pool ran clear. Hozier turned to look at Danu. His brown eyes had gone gold at the edges, like the shadow-horse's had been. He smiled once, small, to show her he was still himself. For now.