It's been three years and then some since I last took a look at this fic, but it's worth finishing right. Standard disclaimer still applies, though JKR's more recent work has left it quite AU.
Rosemary for Remembrance
Part Two—Life's But a Walking Shadow
Harry began to raise his head, faintly disbelieving.
Pop; Pop, pop, pop, POP—
Along with the black-robed wizards came a cacophony of noise.
"Mr. Potter! Congratulations! The Ministry of Magic would like to—"
"By Merlin's b—"
"Any words for your adoring public, Harry?"
"Excuse me, ma'am, did you—"
"What?" replied Harry dully. Where had they all come from? How did they—
"—first time seeing magic, I see—"
"Harry, my dear boy," broke in the all-too-familiar voice of Cornelius Fudge, "we always knew you could do it. So proud, my boy, so proud."
" 'We' always knew—you—"
"Now, now, Harry," Fudge cut in hastily, offering him a nervous smile and a helping hand. Harry ignored both.
"How did you even know Voldemort was dead?"
"Er, well, hm!"
A nearby lackey jumped in: "Mr. Potter, how exactly did you destroy You-Know-Who? Suddenly all the tracking scenes went blank—"
But Harry was no longer listening, for he heard the beginning of a word that chilled his blood.
"—thank you for your cooperation, ma'am. If you would kindly look right here? Obli-"
"—viate," finished the painfully earnest young official, before looking around him in bemusement at the sudden silence.
"How dare you," said Harry; he could barely recognize his own voice.
"She's a muggle," replied the young man with genuine puzzlement; "according to the International Confederation of Wizards' Statute of Secrecy, it is standard procedure to…"
He continued to talk, but Harry couldn't heard him, couldn't distinguish anything from the sudden burst of noise behind him. The old woman was looking around her, obviously still confused by the charm. He swallowed painfully as her eyes slid right over him without pausing; she seemed smaller and more fragile than he'd remembered.
"You really want to know how I defeated Voldemort?" he asked, without turning back to the crowd. The room slowly hushed, expectant.
"Only two people in the entire world are alive to tell the tale, and he just Obliviated the only one who'd ever tell you anything."
"Mr. Potter!" they all seemed to cry with one voice—
The old woman rubbed her eyes, sure that she was seeing things. Surely there'd never been a black-haired boy there in the first place; though disappearing boys seemed strangely logical in comparison to the hoard of maniacs in black robes now invading her little cottage.
Why, just now one of them was exclaiming over a broken stick, and calling over all the rest to see. The sudden spike in noise went straight to her headache. She quietly slipped away, hoping that she would wake up soon and find that it was all a dream.
Dear Professor Snape—
No, not quite right. Harry chewed his lip thoughtfully, and erased the latest attempt. Something respectful, but without implying that Harry was still a student.
Ave Salveque, Snape--
I apologize for intruding on your hard-won peace, but I suspect that you've already …
When spring finally came, the old woman began to have trouble getting out of bed.
She smiled at him, gently patting his cheek with her soft, wrinkled hand. "You don't know what it means to me that you are here, young man. Relax. Don't try so hard. I'm ready, and I have company. It's more than I had hoped."
Harry smiled for her, even as he unconsciously clenched his grip on her blankets. The old woman's room was peaceful. He'd discreetly spelled away the sweetly musty smell of sick, and charmed the bed warm before opening the window. It was easier when he had something he could do.
"You saved my life. It's the least I could do."
She snorted quietly in disbelief. "Me?" she replied. "Look at me; I'm old. I'm practically helpless. My memory is going, but I'm still sharp enough to know myself. There's no need to pretend I've earned your kindness."
He let it go, and sat with her in the fading afternoon light. The cat sauntered into the room, and deigned to go curl himself up at the foot of the bed. Birds chirped somewhere outside the window.
It wasn't easy for either of them over the next few days. The old woman drifted in and out of her fever, in and out of her past. She asked for Charles; she scolded him for being a flirt and a charmer. She called him everything except for Harry, and he bore it with a smile.
"My mother doesn't approve," she confided in him one afternoon, "but I like to imagine that the world is stranger and more wonderful than we know. Maybe there really is magic somewhere in the world, and it's right under our noses. That circle of mushrooms could be a gate to the Fair Folk; that bird over there might be able to talk, if he had anything useful to say."
"Really," said Harry mildly, "I bet he'd love to say something cutting," and she burst out into delighted laughter.
Later, he offered to pull out his wand and show her some magic tricks, and she slapped him in the face.