Harry's father nodded. "A well-considered policy for addressing the problem of teachers who don't understand logarithms."
"I was seven years old! How long are you going to keep on bringing that up?"
"I know," said his mother sympathetically, "you bite one maths teacher and they never let you forget it, do they?"
Harry turned to Professor McGonagall. "There! You see what I have to deal with?"
"Excuse me," said Petunia, and fled through the backdoor into the garden, from which her screams of laughter were clearly audible.
"There, ah, there," Professor McGonagall seemed to be having trouble speaking for some reason, "there is to be no biting of teachers at Hogwarts, is that quite clear, Mr. Potter?"
Harry scowled at her. "Fine, I won't bite anyone who doesn't bite me first."
Professor Michael Verres-Evans also had to leave the room briefly upon hearing that.
"Well," Professor McGonagall sighed, after Harry's parents had composed themselves and returned. "Well. I think, under the circumstances, that I should avoid taking you to purchase your study materials until a day or two before school begins."
"What? Why? The other children already know magic, don't they? I have to start catching up right away!"
"Rest assured, Mr. Potter," replied Professor McGonagall, "Hogwarts is quite capable of teaching the basics. And I suspect, Mr. Potter, that if I leave you alone for two months with your schoolbooks, even without a wand, I will return to this house only to find a crater billowing purple smoke, a depopulated city surrounding it and a plague of flaming zebras terrorising what remains of England."
Harry's mother and father nodded in perfect unison.
"Mum! Dad!"
"But then the question is - who?"
"Good Lord," said the barman, peering at Harry, "is this - can this be -?"
Harry leaned towards the bar of the Leaky Cauldron as best he could, though it came up to somewhere around the tips of his eyebrows. A question like that deserved his very best.
"Am I - could I be - maybe - you never know - if I'm not - but then the question is - who?"
"Bless my soul," whispered the old barman. "Harry Potter... what an honour."
Harry blinked, then rallied. "Well, yes, you're quite perceptive; most people don't realise that so quickly -"
"That's enough," Professor McGonagall said. Her hand tightened on Harry's shoulder. "Don't pester the boy, Tom, he's new to all this."
"But it is him?" quavered an old woman. "It's Harry Potter?" With a scraping sound, she got up from her chair.
"Doris -" McGonagall said warningly. The glare she shot around the room should have been enough to intimidate anyone.
"I only want to shake his hand," the woman whispered. She bent low and stuck out a wrinkled hand, which Harry, feeling confused and more uncomfortable than he ever had in his life, carefully shook. Tears fell from the woman's eyes onto their clasped hands. "My granson was an Auror," she whispered to him. "Died in seventy-nine. Thank you, Harry Potter. Thank heavens for you."
"You're welcome," Harry said automatically, and then he turned his head and shot Professor McGonagall a frightened, pleading look.
Professor McGonagall slammed her foot down just as the general rush was about to start. It made a noise that gave Harry a new referent for the phrase "Crack of Doom", and everyone froze in place.
"We're in a hurry," Professor McGonagall said in a voice that sounded perfectly, utterly normal.
They left the bar without any trouble.
"Professor?" Harry said, once they were in the courtyard. He had meant to ask what was going on, but oddly found himself asking an entirely different question instead. "Who was that pale man, by the corner? The man with the twitching eye?"
"Hm?" said Professor McGonagall, sounding a bit surprised; perhaps she hadn't expected that question either. "That was Professor Quirinus Quirrell. He'll be teaching Defence Against the Dark Arts this year at Hogwarts."
"I had the strangest feeling that I knew him..." Harry rubbed his forehead. "And that I shouldn't ought to shake his hand." Like meeting someone who had been a friend, once, before something went drastically wrong... that wasn't really it at all, but Harry couldn't find words. "And what was... all of that?"
Professor McGonagall was giving him an odd glance. "Mr. Potter... do you know... how much have you been told... about how your parents died?"
Harry returned a steady look. "My parents are alive and well, and they always refused to talk about how my genetic parents died. From which I infer that it wasn't good."
"An admirable loyalty," said Professor McGonagall. Her voice went low. "Though it hurts a little to hear you say it like that. Lily and James were friends of mine."