Chapter Text
I. The Quill
The thing about poverty was that it taught you the weight of everything.
Tom Riddle knew the exact cost of a standard eagle-feather quill (seven Sickles), a bottle of Blott's Ever-Black Ink (twelve Sickles for the half-pint, nine if you caught the August sale at the secondhand stall in Knockturn Alley), and a ream of passable parchment (one Galleon, two Sickles, though you could halve the cost by writing on both sides and in margins if the professor wasn't particular). He knew because he had to. Hogwarts provided tuition and board, but everything else came from the small vault the school maintained for its scholarship students. Forty Galleons a year. It sounded generous until you did the arithmetic, which Tom had done in his first week, sitting cross-legged on his bed in the Slytherin dormitory with his secondhand copy of Hogwarts: A History open in his lap. Not reading. Just calculating.
Forty Galleons. That was textbooks (secondhand, if he was careful), ingredients for Potions (supplemented by what he could forage from the grounds on weekends), parchment and ink and quills, and whatever was left over for incidentals. There was never anything left over. A new quill meant fewer Potions ingredients. A replacement cauldron lid meant no ink until February. Every Knut was a negotiation with a future version of himself who would go without.
He was in his third year now, and the arithmetic hadn't changed. What had changed was his skill. Tom had become very, very good at making things last. His school robes, bought secondhand from a graduating Slytherin his first year, had been let out twice at the hem with careful Lengthening Charms and re-stitched by hand along the seams where the fabric was weakest. His Potions knife was nicked and dull, but he'd learned a Sharpening Charm from a library book that wasn't strictly on any curriculum. His quills, all three of them, the best growing bald on the left side, wrote perfectly well if you adjusted your grip.
He did not complain about this. Complaining implied that someone should fix it, and Tom Riddle did not rely on anyone to fix anything.
It was a Thursday in late September when Harry Potter dropped a quill.
Tom had noticed Potter, of course. Everyone had noticed Potter. The Sorting of Harry James Potter, Heir to the Ancient and Noble House of Potter, into Gryffindor House had been accompanied by thunderous applause two years prior, a standing ovation from half the staff table, and a burst of accidental magic from the Weasley twins that sent sparks showering from the enchanted ceiling. Tom had watched from the Slytherin table with the careful blankness he reserved for moments when other people had things he did not.
Heir Potter was everything Tom expected: loud, careless, bright in the way that people who had never known darkness could afford to be. He left his belongings scattered across common areas like a boy who had never had to account for a single possession. Scarves on benches. Books on windowsills. Quills, expensive, barely used eagle-feather quills, everywhere. He was small for a first-year, all messy black hair and round glasses and a grin that was too wide for his face.
Tom, at thirteen, was already tall. Taller than most of his yearmates, with dark hair, sharp features, and the kind of symmetrical face that drew second glances in the corridors. He'd caught older students looking, professors too, the brief double-take of people encountering something unexpectedly striking in a place they hadn't expected to find it. The handsomeness was almost cruel in its irony: a face that could have belonged to old money, to a boy who summered in the south of France and wore robes cut by Twilfitt and Tatting's, paired instead with secondhand wool and ink-stained cuffs and the careful, guarded expression of someone who owned nothing worth stealing.
It happened in the third-floor corridor. Tom was coming from Ancient Runes, walking quickly because he wanted to reach the library before the good tables were taken, when he saw it: a quill on the flagstones, still rolling slightly, as if it had just fallen from someone's overstuffed bag. He looked up and saw Potter ahead of him, rucksack open and spilling parchment, laughing at something the youngest Weasley boy was saying.
Tom picked up the quill. He turned it in his fingers. An eagle-feather, yes, but a premium nib. Self-inking. The kind that cost two Galleons and lasted a year with regular use. The kind that Tom had looked at exactly once in the shop window and then looked away, because two Galleons was the difference between new Potions ingredients and three weeks of improvisation.
"Potter."
The boy turned. He had to look up to meet Tom's eyes. He was small, barely reaching Tom's shoulder, and his expression was one of perpetual guileless surprise, as if the world kept delighting him and he hadn't yet learned to hide it.
"You dropped this."
Potter looked at the quill, then at Tom, and grinned. The grin was crooked and completely unselfconscious.
"Oh, cheers! Keep it, though, I've got loads. Mum sends them by the box."
He turned back to Weasley and kept walking, and that was it. That was the entire interaction. Three seconds, maybe four, and Potter had already forgotten it.
Tom stood in the corridor holding a quill that was worth more than his entire supply budget for the month, and thought: What does he want?
Because people didn't give things away for nothing. Tom had learned this before he'd learned to read. At the children's home, every act of apparent kindness was a transaction. The older children who shared their food wanted something. The carers who smiled wanted compliance. Mrs. Cole, who occasionally gave Tom a secondhand book, wanted to tell the board of governors that she was nurturing her charges' development. Nothing was free. Nothing was without angle.
He examined the quill. Self-inking, as he'd suspected. The nib was perfect, sharp, even, without a single scratch. It wrote like water over glass.
He used it to take his Ancient Runes notes the following day, and the day after that, and every day for the next three years. He stored it in a leather sleeve he'd made from a scrap of old binding. He re-sharpened the nib once a term with a precision that bordered on ritual.
It was the nicest thing he owned.
He kept waiting for Potter to come collect on the debt, but Potter never did.
* * *
II. The Book
The library became theirs by accident.
Tom had claimed the table in the far back corner of the Restricted Section's antechamber, where the light was poor and the chairs were hard and no one went unless they were serious about being left alone. It was Tom's table in the way that certain things became yours through sheer, stubborn persistence: he was there every evening from dinner until curfew, and every Saturday from breakfast until lunch, and eventually the other students stopped trying.
Potter found it in October of Tom's fourth year.
Tom heard him before he saw him. The Gryffindor's footsteps were unmistakable, too quick and slightly uneven, as if he was always on the verge of breaking into a run. Tom didn't look up from his Transfiguration essay. He was in the middle of a delicate argument about Gamp's Law and didn't intend to lose his thread for a second-year who'd taken a wrong turn.
But Potter didn't leave. He stood at the edge of the table for a moment, breathing slightly too fast, and then pulled out the chair across from Tom and sat down.
Tom looked up.
Potter's face was flushed. His glasses were askew. He looked like he'd been running from something, which, given that the Weasley twins had recently discovered how to enchant dungbombs to pursue specific targets, was entirely plausible.
"This seat taken?"
"Does it matter? You've already sat down."
Potter's mouth twitched. "Fair point."
He pulled out a Defense Against the Dark Arts textbook, opened it to a random page, and stared at it with the fixed intensity of someone who was absolutely not reading. Tom watched him for five seconds, then returned to his essay.
They didn't speak for two hours. When curfew came, Potter packed up and left with a mumbled "Thanks" and a wave that Tom didn't return.
He came back the next evening. And the next.
By the third week, Tom understood: Potter was hiding. From what, Tom didn't know. The Weasley twins' experiments, perhaps, or the exhaustion of being the most looked-at boy in school. The weight of being Heir Potter, of having every professor compare you to your father's brilliance and your mother's charm, of carrying a name that opened doors you hadn't chosen to walk through. Whatever the reason, Potter had discovered that the back of the library was quiet, and Tom was quiet, and sometimes that was enough.
Tom should have minded. He valued his solitude fiercely, possessively, because it was one of the few things he had that cost nothing. But Potter was surprisingly tolerable as a study companion. He didn't fidget excessively. He didn't try to make conversation unless Tom initiated it. He chewed on the end of his quill when he was thinking, which was barbaric and wasteful, but at least he was quiet about it.
The conversations, when they happened, were unexpected.
"You're reading the Jigger, right? The Advanced Potions text?" Potter asked one evening, eyeing the book propped open against Tom's bag. "Is it good?"
"It's adequate." It was better than adequate. It was the most comprehensive text on advanced brewing theory available to a Hogwarts student. Tom had seen it in Flourish and Blotts during the summer, stood in the aisle running the numbers (one Galleon fourteen Sickles, minus the cost of replacement quill nibs he'd need by October, minus the Potions ingredients for the autumn term), and put it back on the shelf. His current copy was a third-hand edition with a cracked spine, water stains on the Draught of Living Death chapter, and seven pages held in by Permanent Sticking Charm. "Why?"
"I'm terrible at Potions. Snape hates me. I thought maybe if I read ahead..."
"Snape hates everyone. Reading ahead would help, but you're two years away from needing this text."
"So? I can still read it."
Tom studied him. Potter looked back with that open, earnest expression that Tom found deeply suspect in its apparent sincerity.
"If you want to improve your Potions work, start with Libatius Borage's introductory text. Master the basics before you attempt advanced theory."
Potter nodded seriously, as if Tom had handed him a battle plan. "Right. Borage. Got it."
The following evening, Potter arrived at the table with two books. One was the Borage. The other was a brand-new copy of Arsenius Jigger's Advanced Potion-Making, the current edition, with a pristine spine and pages that hadn't yet been creased.
"Flourish and Blotts sent me two by mistake," Potter said, placing the Jigger in front of Tom with studied casualness. "Mum already sent back the receipt, so we can't return it. D'you want it? Seems stupid to waste it."
Tom looked at the book. The cover was immaculate. The gilded title caught the candlelight. He could smell the binding, fresh leather and new ink, the scent of something that had never belonged to anyone else.
Flourish and Blotts did not send books by mistake. Lily Potter, nee Evans, first-class Arithmancer and famously precise woman, did not fail to notice duplicate orders. This book had been bought deliberately, by a twelve-year-old boy who had noticed that Tom's copy was falling apart and had constructed a transparent lie to disguise an act of charity.
Tom should have refused. His pride demanded it, hot and sharp, climbing up his throat like bile. He had survived twelve years of the children's home and three years of Hogwarts on nothing but his own mind and his own hands, and he would rather write his N.E.W.T.s with his water-stained, crumbling, Sticking-Charmed edition than accept handouts from a boy who thought poverty was a problem that could be solved with a trip to the bookshop.
But the book was beautiful. And Tom's copy really was falling apart.
"Fine," he said. "Thank you."
Potter beamed. The force of it was almost physical, like stepping into sunlight after a long time underground.
They studied together after that. It became routine: evenings and Saturdays, the back table, Tom's neat handwriting and Potter's messy scrawl side by side. Tom helped Potter with Potions theory. Potter, who turned out to have a startling intuitive grasp of defensive magic, occasionally surprised Tom with an insight about curse-breaking or counter-jinxes that was genuinely useful. Tom didn't have friends. He had an arrangement. A mutually beneficial exchange.
Granger noticed.
She appeared at the table one Saturday in November, books clutched to her chest, and fixed Tom with a long, measuring stare. "Harry's Potions marks have gone up two grade levels since he started studying with you."
"He's been applying himself," Tom said blandly.
"He's been applying himself identically in every other subject. Only Potions has improved." She held his gaze for three seconds, an eternity by Granger standards, and then turned to Harry. "Dinner's in twenty minutes."
After she left, Harry said, "Don't mind Hermione. She notices everything."
"Yes," Tom said. "I'd gathered."
He filed Granger away as someone to watch. She was too clever by half, and clever people were dangerous, because they saw patterns that were supposed to stay hidden.
Weasley was a different problem. He arrived at the table the following week, sat down without being invited, and said, with the directness of someone who had never learned to be diplomatic: "So you're the reason Harry's always in the library now."
"Harry is in the library because he chooses to be."
"Right." Weasley looked at him, freckled face unreadable. "Just so you know, if you're messing with him, I'll find out."
"Noted," Tom said.
Weasley stared at him for another moment, seemed satisfied with whatever he found, and left. Tom watched him go and felt a faint, grudging recognition settle somewhere beneath his ribs. Loyalty, even badly expressed, had a certain value.
And Tom intended to keep the arrangement exactly as it was.
The quill had taught him the first rule: debts accrued interest. Every gift Potter gave him, and Potter kept giving with the careless generosity of someone who had never learned to count, was a line in a ledger that Tom maintained with the same ruthless precision he brought to everything. The quill: two Galleons. The book: one Galleon, fourteen Sickles (he'd checked the price at Flourish and Blotts, standing in the aisle, running the numbers he already knew by heart). Each gift demanded repayment, and Tom repaid the only way he could: with his mind.
It started with Potions. Potter was, as he'd freely admitted, terrible. Tom began correcting his work. Not ostentatiously, not in the way a tutor would, but quietly, surgically. He'd glance at Potter's essay while Potter was fetching a book and catch the errors: the misspelled ingredient, the reversed stirring direction, the conclusion that didn't follow from the evidence. When Potter returned, Tom would say, casually, "Your third paragraph contradicts your second. You've confused aconite with acromantula venom again." Potter would groan and fix it, never questioning why Tom had read his essay at all.
Then it spread. Tom proofread Potter's Transfiguration homework and offered "suggestions" that amounted to rewriting the weak sections. He caught a critical error in a Charms practical, a wand movement performed in mirror that would have rebounded the spell, and corrected it with a murmured "Other hand, Potter" that Potter absorbed without thinking. He began, with increasing deliberateness, steering their study sessions toward whatever subject Potter had an exam in next, sacrificing his own revision time to ensure Potter's marks improved.
Potter's grades climbed. Not dramatically; Tom was careful about that, since a sudden leap would draw attention. But steadily. A P became an A. An A became an E. Potter's Potions essays, in particular, went from borderline failures to competent work, and if Snape noticed the improvement, he said nothing, because Snape noticed very little about Harry Potter that wasn't a reason for contempt.
Harry didn't realize. That was the essential thing. He didn't notice that Tom had become his invisible academic scaffolding, that the "casual tips" and "quick corrections" amounted to hours of Tom's time. Time Tom could have spent on his own work, his own ambitions, his own meticulous campaign for academic perfection. Potter would beam at his improved marks and say, "I think your study methods are rubbing off on me!" and Tom would allow himself a thin smile and add another line to the ledger.
Quill: repaid (twelve hours of Potions tutoring). Book: repaid (Transfiguration and Charms revision, ongoing). Balance: pending.
Everyone wanted something. Tom simply preferred to pay his debts before they were called in.
And Potter kept giving him things.
It was never overt. Never a wrapped package or a declared gift. Always casual, always deniable. A box of Honeydukes chocolates pushed across the table: "Mum sent too many, I'll be sick if I eat them all, have some." A new bottle of ink: "Scrivenshaft's had a sale, I grabbed an extra." Warm gloves in December: "These don't fit me anymore, the house-elves will just bin them."
The gloves fit Tom perfectly.
He took the things. He told himself it was practical; waste was inefficient, and refusing would make Potter ask questions. He took the chocolates and ate them alone in his dormitory, one per night, making them last two weeks. He took the ink and used it sparingly, a single dip where another student might use three. He took the gloves and wore them until they were threadbare and then he darned them with wool from his unravelled scarf.
And for each gift, Tom added a line to the ledger and worked a little harder on Potter's essays, stayed a little later to help with revision, caught one more error, offered one more correction. The ledger never balanced. Potter gave faster than Tom could repay, and the debt grew, and Tom lay awake at night doing the arithmetic and feeling the walls close in.
Potter never asked. Never hinted. Never so much as glanced at the ledger Tom was keeping with the desperate meticulousness of a man trying to stay solvent. Potter just gave, and smiled, and went back to chewing his quill, and Tom could not decide if this was kindness or the most sophisticated form of control he'd ever encountered.
Then there was this: a Saturday in February, Potter watching Tom repair a tear in his robe with needle and thread. Muggle thread, because Mending Charms were only as strong as the fabric, and this fabric was thin as parchment in places.
"Your robes are a bit short, aren't they?" Potter said, with the devastating innocence of someone who had never in his life worn the same robes two years running. "Why don't you just owl Madam Malkin's? She does adjustments."
Tom's needle paused. His jaw tightened, a fracture in the mask so small that anyone else would have missed it.
"I'll manage," he said.
Potter didn't notice the edge. Of course he didn't.