Gillie Blue stopped at the edge of the third wrong clearing and knew the grove had moved again. She had been walking for two hours. She had passed this same split birch twice. Somewhere past it, her friend was still trapped, the one who had followed her in a week ago and not come out. She tightened her grip on the hiking stick her father had cut for her. A good stick keeps you honest on uneven ground, he'd said. She needed honest ground now more than she ever had. Small eyes watched her from the moss. A beetle the size of her thumb. Two mice on a root. A thrush with its head tipped sideways. She had felt them the whole morning, tracking her from branch to stone to branch. The groves hurt people who lingered. She could already feel it in her teeth, a low ache like cold water. She crouched and set down her purple backpack. "He came through here," she said to the beetle. "Tall. Loud laugh. Red jacket. Which way did they take him?" The beetle turned in a slow circle. The mice sat up. The thrush hopped one branch closer and made a sound that was not quite a word. Gillie waited. She tried the few forest words her father had taught her for luck. She tried pointing. She tried drawing a jacket in the dirt with the tip of her stick. The thrush cocked its head the other way. The mice went back to grooming. Whatever they knew, she could not reach it. The language was a wall. She sat down hard in the leaves. For the first time since she'd entered the grove she let herself say it out loud. "I can't do this alone." The light changed. It came between two pines, slow and white, and at first she thought it was only sun breaking through. Then the sun stepped forward on four hooves. A unicorn, small as a young horse, its mane streaked with pale blue, a single horn catching the light like wet glass. It stopped ten feet from her and lowered its head until its eye was level with hers. Gillie did not move. The ache in her teeth eased. The unicorn looked at the beetle. The beetle lifted one leg and pointed, clean and certain, toward the dark line of trees behind the split birch. The mice turned the same way. The thrush called once and flew in that direction. The unicorn took two steps after the thrush and stopped. It looked back at her. Gillie stood. She shouldered the purple pack and picked up her stick. "Okay," she said. "Show me." She followed the unicorn past the split birch, into trees she had not been able to enter alone.

The dark trees closed over Gillie and the unicorn like a lid. Under the split birch the air had held some sun. Ten steps past it, the light thinned to gray. Gillie could still see the unicorn's white flank ahead of her, but the trail between the roots was already going soft at the edges. She checked her watch. An hour until dusk, maybe less under this canopy. She had a flashlight at home on the kitchen counter. She had matches in the pack, but nothing dry enough to burn long. If night fell here, she would lose her friend's trail and probably her own. The unicorn stopped. It looked back at her, then at the ground. Gillie crouched. A boot print, half filled with leaves. Red thread caught on a thorn. Her friend had come this way. She pressed the thread flat against her palm and made herself breathe. "I need light," she said. "I can't track him in the dark." The unicorn walked to a thick stand of ferns beside the path. It lowered its horn and touched one frond. Gillie pushed the fronds apart with her stick. A butterfly sat on the underside of a leaf. Its wings were the color of a lit lamp. A red ladybug clung to its back. When the butterfly opened its wings, the ground under the ferns turned gold. Gillie could see every root, every beetle, every wet stone. She held out her hand slowly. The butterfly stepped onto her knuckle. The ladybug did not move. The light came with them, a small clean circle around her fist. "Thank you," she said. She meant it for all three of them. She stood and lifted her hand. The circle widened enough to show the next boot print, and the next. The unicorn started walking again. Gillie followed with her stick in one hand and the butterfly in the other. Above the canopy the sky was going the color of iron, but inside her circle it stayed bright. They walked for a long time. The prints led downhill, then along a shallow creek, then up between two mossy boulders. Gillie kept her hand steady. The butterfly did not tire. At the top of the rise she stopped. Below her, in a hollow choked with vines, something red lay on the ground. A jacket sleeve. Not moving. Gillie's throat closed. She started down the slope, faster than the unicorn, faster than was safe. Her stick caught a root and she stumbled but did not fall. The light in her hand bounced with her. She reached the hollow. The sleeve was empty. The jacket had been torn off at the shoulder and left in the dirt like a marker. Something had taken him further in. She closed her fist gently around the butterfly and looked at the unicorn. "Deeper," she said. "We have to go deeper."