"Like being put in a cage," she answered, uncertain if that would tell Greta anything. "Unicorns are immortal, humans are not. Being an immortal trapped in a mortal body is... distressing."

When they reached the edge of Cabeswater it happened in a faint flash of light. One moment there was a unicorn moving forward, and the next there was a pale girl falling to her knees, only the fall of her long, white-blond hair offering any modesty. Amalthea curled her legs beneath her, hiding herself for a moment as she recovered from the change.

"I put clothes over there," she said with a faint point towards a rock; her voice was the same. There was a backpack there. Eventually she lifted her head, looking at Greta with the unicorn's eyes from the face of a girl.