Erin was sleeping on the floor of Ginny's room. Not as uncomfortable as it sounded - at least ten blankets kept her warm and snug. Erin turned in her sleep, murmuring nonsense as dreamed. Not a bad dream either - she and Harry had thrown Dudley into a lake of hot chocolate and were celebrating by doing cartwheels and handsprings. Then, like somebody turning the TV off, the dream stopped. To be replaced by something even stranger.

Erin was standing alone in a forest. It was late at night, and the only light came from the stars and the moon, but Erin wasn't afraid. Standing opposite her was somebody she'd never seen before - a man, cloaked completely in black, and astride a shimmering white unicorn. The man dismounted the unicorn smoothly and came to stand by Erin's side.

"Erin," he murmured.

"Bryan," she said in return, not knowing how she knew his name but sure that that was it. "Wind-Runner," she added to the unicorn, which tossed its head in reply.

The man lifted his hands to the hood of his cloak and began to push it off his face. Erin, eager to see, leaned forward. She had only the swiftest glimpse of his eyes - bright, clear blue eyes that somehow shimmered the same way that the unicorn did.

Then the man appeared to change his mind, and lifted his cowl back up.

"Bryan," said Erin, exasperated in a way she could not understand. "You can't-"

But it was too late, for the unicorn was already galloping past her, and with a single swift leap the man was once more astride it, lying flat along its back and clinging to the silvery mane. They were gone, and Erin stood all alone in the forest.

She woke up to hear Mrs. Weasley calling them for breakfast.

Severus looked at the bit of paper in his hands. A letter of admission, like the one so many other students would be receiving this year. But this one was going to Erin.

Severus tied it carefully to the leg of one of the school owls, a large barn one. "Deliver it safely," he sternly instructed the owl. The owl appeared to understand, for it flew much more carefully than it might have with any other letter. Severus watched it through the window of the Owlery for a moment, then descended back down the stairs. To the dungeon, where his lesson plans were waiting.