Albus Dumbledore put down the ominoculars and sighed. "Oh the poor boy," he said softly.

"Who?" demanded Snape. "Harry?"

"No," said Dumbledore. "Quirinius." Snape opened his mouth to object but Dumbledore continued. "Severus, I can conceive of a Quirinius Quirrell consumed with a lust for gold, or immortality or even power. I cannot easily conceive of a Quirinius Quirrell consumed with a lust for the death of an eleven year old boy. I fear poor Quirinius is no longer alone in his own mind."

Snape sat back in the uncomfortably comfortable chair, winded. "Possession? But what...?" And then he realised and his blood ran cold. "Then He has returned." Not only returned but dividing his attention between Harry and the Philosopher's Stone. "What are we going to do?"

Dumbledore steepled his fingers for a moment and considered before answering. "Not we, Severus, this time at least it must be me and me alone." Then before Snape could protest. "My dear boy, if it is as we fear, we cannot risk Voldemort seeing we two allied. No matter how small the risk may be, I'm unwilling to take the chance in case we need your services as a spy in the future."

"You cannot be thinking of challenging him alone?"

"Tom has been afraid of me for over 50 years, in his current state there is little or nothing he can do to me even if he wished to. No, my only fear is that I will not manage to contain him long enough for us to discover why he did not die that night in Godric's Hollow."

"When?"

"He has a free period last thing this afternoon. I will ask Hogwarts to confine the students and staff in whatever room they find themselves and confront him then. And yes, Severus, I am quite sure."

There was nothing he could do except wait. Third year Griffs and Snakes got away with murder, and he was obliged to vanish every single half-completed potion in the room when a particularly vicious round of sabotage began under his very nose. The tongue-lashing they received would have been remembered on its own account, even if it had not been interrupted by a hollow boom which shook the castle, even down in the dungeon.

Hogwarts must have been as worried as Snape, since the doors swung upon as he ran towards them and up the stairs to Quirrell's rooms. The door was open and a foul smell lingered in the corridor outside. As the youngest member of staff, and the only one with advance knowledge of the afternoon's excitement, he arrived first. He approached cautiously, wand in hand but he need not have bothered. Dumbledore appeared totally unscathed, standing over the huddled body of the Defence Against the Dark Arts professor. "Headmaster?"

"Come in, Severus, and close the door."

Snape did so reluctantly; there was something nauseatingly unnatural about the way Quirrell was lying and it took him a moment to work out what it was. The head was looking at him over its left shoulder. He swallowed hard. "What in hell's name is that?"

Dumbledore gestured and the ends of Quirrell's robe flew up to cover his head. "That, my boy, is the most advanced case of corporeal possession I have ever seen. Poor Quirinius was no match for Tom and was being eaten away to provide him with a habitation. Without the Stone, he would have died in a matter of weeks, possibly even days." They could hear voices outside and someone, braver than the rest, began knocking on the door. Dumbledore raised his voice. "All is well," he called. "I will be out in a moment or two, please make sure the corridors are clear of students." The voices outside sank to a confused babble.

"You couldn't contain him?"

"No. He left Quirinius as some form of wraith but despite my, not inconsiderable, best endeavours he was impervious to both Thorogood's Holding and Wellesley's Lock." With a flick of his wrist, he conjured a thick, black blanket and used it to wrap the body. "I'll take the poor boy up to the infirmary and call the Aurors. Will you check on Harry, please? He should be in um... Herbology at the moment. Tom asked after him, and while I of course told him nothing, I would be easier in my mind if you saw him."

"You are sure The Dark Lord is..."

"Severus, how many times must I ..."

"Very well, are you sure Voldemort." He could not contain the shudder. "Is gone?"

"Oh yes," Dumbledore was magnificently certain. "Without a body to anchor and hide him, he could not remain within our wards. He was expelled, and rather violently too. When I saw I could not contain him, I did my best to help him on his way. I doubt he is even in the country at the moment. Severus, we can discuss this later, our colleagues will not wait much longer." So saying, he levitated the body from the floor and opened the door to reveal a cluster of anxious staff members.

Snape left them exclaiming and protesting and hurried down to the greenhouses, where he was glad to see Pomona Sprout had had the excellent sense to confine her first year class. As he gave Sprout what little information he felt secure in revealing, he looked round for Harry.

He found him sitting on the floor, his little friends on either side of him propping him up and urging him to drink from a glass of water.

"What is wrong with Potter?"

Sprout frowned. "I'm not quite sure. Just as we heard the noise from the castle, he cried out and clutched his forehead. Some form of morphic resonance, perhaps. He is very sensitive to magic in all its forms. He was very much shaken earlier but seems to have recovered nicely."

The bell rang for end of school and the usual ill-mannered clamour broke out, as the pupils packed up their books, put way their gardening tools in a slipshod manner he would never have countenanced and made a dash for the door. "Mr Potter," called Snape above the hubbub and was gratified by the smile on the boy's face as he fought his way out of the crowd by the door. "I have spoken to Professor Flitwick and he will be announcing open auditions for the choir later this week."

For a startled moment, he was sure Harry was about to embrace him. He even saw the moment the boy realised what he was about to do, and stopped himself. "Oh thanks, Professor. You didn't say anything at breakfast and I thought you'd forgotten. I should've known you wouldn't." They fell into step as they both headed back to the castle, Harry almost bouncing in his excitement. "I wonder what we'll be singing. I asked Ron and Hermione if they wanted to come but Hermione says she's can't sing for toffee. She says lots of magical people can't. Is that why the School Song is so horrible?"

"I confess I have never devoted much thought to the matter. It is true that musical talent is rare among wizarding kind, and is consequently greatly prized when it is found."

"Can you..."

"Regrettably not."

It was cold outside, and the memory of what he had seen upstairs made him all the more glad to step into the light of the Great Hall. He was just beginning to realise. It was happening again. War with all its ugliness: the spying, the fear, the betrayals.

He looked down at the elated boy at his side, and saw how precious was his innocence; and knew it would soon have to be sacrificed to save his young life.