Quirrell smiled. His face wasn’t twitching at all.
“Me,” he said calmly. “I wondered whether I’d be meeting you here, Potter.”
“But I thought—Snape—”
“Severus?” Quirrell laughed, and it wasn’t his usual quivering treble, either, but cold and sharp. “Yes, Severus does seem the type, doesn’t he? So useful to have him swooping around like an overgrown bat. Next to him, who would suspect p-p-poor, st-stuttering P-Professor Quirrell?”
Harry couldn’t take it in. This couldn’t be true, it couldn’t.
“But Snape tried to kill me!”
“No, no, no. I tried to kill you. Your friend Miss Granger accidentally knocked me over as she rushed to set fire to Snape at that Quidditch match. She broke my eye contact with you. Another few seconds and I’d have got you off that broom. I’d have managed it before then if Snape hadn’t been muttering a countercurse, trying to save you.”
“Snape was trying to save me?”
“Of course,” said Quirrell coolly. “Why do you think he wanted to referee your next match? He was trying to make sure I didn’t do it again. Funny, really… he needn’t have bothered. I couldn’t do anything with Dumbledore watching. All the other teachers thought Snape was trying to stop Gryffindor from winning, he did make himself unpopular… and what a waste of time, when after all that, I’m going to kill you tonight.”
Quirrell snapped his fingers. Ropes sprang out of thin air and wrapped themselves tightly around Harry.
“You’re too nosy to live, Potter. Scurrying around the school on Halloween like that, for all I knew you’d seen me coming to look at what was guarding the Stone.”
“You let the troll in?”
“Certainly. I have a special gift with trolls—you must have seen what I did to the one in the chamber back there? Unfortunately, while everyone else was running around looking for it, Snape, who already suspected me, went straight to the third floor to head me off—and not only did my troll fail to beat you to death, that three headed dog didn’t even manage to bite Snape’s leg off properly.
“Now, wait quietly, Potter. I need to examine this interesting mirror.”
It was only then that Harry realized what was standing behind Quirrell. It was the Mirror of Erised.
“This mirror is the key to finding the Stone,” Quirrell murmured, tapping his way around the frame. “Trust Dumbledore to come up with something like this… but he’s in London… I’ll be far away by the time he gets back…”