6:55pm, 1 September 1938

The Great Hall of Hogwarts bore a certain resemblance to the interior of Salisbury Cathedral. Its ceiling – an apparition of an arctic night sky (indeed replete with aurorae borealis) reflected in an ebbing, viscous screen of purely transparent liquid – did not. Mary, however, was completely unmoved by this artefact of sublime magical craftsmanship; she yearned for Salisbury Cathedral's sharp, mundane arches, for the morning light sieving through its stained glass windows, for the chocolate eggs of Easter Eucharist.

But Mary was far from Anglicanism and Salisbury, so she wished she was dead. For cursed must be the womb in which a creature like Thomas Riddle could be produced; doubly cursed must be she, for sharing that womb with him. But the brightness of the false overhead stars did not permit her to die, so she felt something else – anger. Anger at Thomas Riddle for his wretchedness; anger that what should have been a beautiful first impression of Hogwarts was wholly subverted by this anger; anger at herself for having been such a fool, for letting her viper of a brother bite her breast.

She even felt angry at Dumbledore, for withholding the full truth of her twin's nature, for appealing to her softer instincts with that old tintype of Thomas which masked the greater part of his grotesquerie (though those eyes were already full of ominous fervour); for thrusting upon her the unbearable duty of tending to such a fiend – for she was not only no saint, but in that moment required herself saintly intercession. But there were no saints at cold Hogwarts, so her anger only festered. Thomas must suffer as he had made her suffer; and Mary knew precisely how to orchestrate such justice.

Thomas was pathologically covetous; no mind-reading was needed for that (Mary had not anyhow entered Thomas's mind, heeding Professor Dumbledore's words, it is unwise to pry into the mind of a wizard, you may see things you wish you hadn't – such likely held truer for Thomas Riddle than most boys present in the hall). His voracious physicality on the train, in both its tender and violence aspects, was enough a testament to that aspect of his character.

When 'Black, Walburga' with enchanted darkish hair and arrogant air that suggested not just a magical upbringing, but a socially advantaged one at that, was sorted into Slytherin, Mary seized the hand of the boy next to her – the pale, solemn but not unhandsome boy named Pavel, with whom she had shared the boat across the Black Lake, but had otherwise little conversed with – and gave it a squeeze. She intertwined their fingers and lay her head on his shoulder; and squeezed again when Pavel glanced at her questioningly.

At first, Pavel was unsettled by Mary's sudden affection – she was little more than a stranger to him – but what boy, solemn or not, did not appreciate a beautiful girl spontaneously resting her head on his shoulder? He squeezed back.

"Hill, Arthur!" Professor Merrythought called. A boy with messy brown hair and a simple, sprightly manner, whose robes were too large for him, placed himself on the stool. "GRYFFINDOR!"

Suddenly, Mary felt something hard and bony clamp her wrist – Thomas was dragging her from Pavel with such force that she nearly stumbled. A few sniggers sounded; Mary found the ordeal less amusing than she should have; she should have known that Thomas would respond immediately and decisively to any provocation.

"Paskevich, Pavel!"

Pavel glanced back at Mary as he went to the stool. She smiled at him abashedly, hoping he forgave her for instrumentalising him against Tom – but he apparently did not realise he had been manipulated, or did not mind.

"GRYFFINDOR!" The hat had taken longer to sort Pavel than most previous students.

Pavel seated himself next to Arthur Hill, who with adorable boy-machismo shook hands with him.

"Riddle, Mary!" Professor Merrythought called. Four seconds elapsed until Tom let her go.

For so old and beaten an object, the hat was unexpectedly soft and cool against her Mary's scalp. She plotted wildly to avoid the fate of sharing a house with Thomas, but her nascent plans, all incoherent, were dashed by a voice suddenly resounding in her head.

My, my, long have I awaited the return of your lineage! I had nearly lost hope – but here you are, Mary Riddle, at last.

Mary was taken aback. Return of my lineage? Have I magical ancestors?

It is not my place to say; though I would counsel you not to dwell excessively upon it – time is an arrow, Mary Riddle; there is nothing to be gained in seeking to defy it.

Mary's curiosity, and perhaps a little bit of her pride, were piqued by this comment; it suggested that her ancestry was somehow noteworthy. But she also sensed that the hat also took perverse pleasure in leaving her guessing, and that asking further would avail her little. She reined herself in; shared ancient heritage or not, she could not bear being Thomas Riddle's twin sister another moment longer. I hope to be sorted into a different house from whichever my brother might be put into.

Your brother? Which? Ah, yes, Thomas. Why should you desire separation from him?

He has done me wrong; you can see that.

Yet it seems he wishes to remain close to you.

Well, I don't wish to remain close to him. He's rather monstrous.

Hmm, yes, yes. But he has yet to be sorted, correct?

Mary was confused – surely the hat could, through the examination of her memories, determine Thomas's character, so violently impressed in the tender parts of Mary's psyche as it was in that moment – but she answered affirmatively nonetheless.

Then time remains on our side, does it not?

Time for what?

Why, for you two quarrelsome children to reconcile! The hat declaimed emphatically. Come now, Mary, how often have brothers and sisters quarrelled – and not infrequently reconciled?

I met Thomas for the first time today! We may as well be strangers.

But you shared the womb, Mary Riddle; surely that must count for something.

What inanity, hat – a bloodless, fleshless object making a reductio ad naturam – are you completely daft?

You are young, Mary Riddle, and anger makes fools of us all – even witches and wizards. You would do well to learn humility; and patience – it may well be that you will need both for Thomas Riddle.

You speak as if he is a disease or economic depression.

Do you truly not understand, Mary Riddle? Thomas Riddle is yours; whether you wish it or not, you are his. Fate has chosen both of you to be together. He has no one else; do you truly wish for him to be alone? Do you really think he is so dissimilar from yourself?

I share nothing with him –

You both thirst for power over those you love; you both resent those who you believe to have power over you; and you both are terribly lonely – and it is this loneliness which consumes you. Mary Riddle, you are closer than twins – you are reflections of one another.

Mary's mind quietened for a moment; she hated to admit it, but the hat was right about her loneliness. But Thomas - he was much worse than she; he was wicked to the core. And she could not help but think that the nature of their respective 'lonelinesses' differed – Mary sought connection, companionship, friendship, love; Thomas, she feared, craved mastery – over others; over himself. Mary trembled at the thought of being mastered; she refused to become a slave to Thomas's whims, to allow him to stifle her. But Mary still had not any friends; Hogwarts was unfamiliar; Pavel had already gone off with Arthur Hill, likely not to be seen again –

But your brother can give you what you seek – he desires closeness with you; and he needs you to temper his worst impulses.

Now you reiterate Dumbledore's prattle; I am not Thomas's keeper.

Yet you care for your brother, do you not? Even if only a little; even if you deny it to yourself; even if only in spite of yourself?

Mary considered for a moment – but was loath to admit that she cared for Thomas, however little. The hat understood this; it probed further.

Would you wish for Thomas Riddle to be unhappy? Would you wish for the continuation of his loneliness?

No.

Would you wish for Thomas Riddle to inflict suffering upon others?

No.

Then it is not impossible for him to reform, Mary Riddle. Will you not help him, then? Will you not try to foster temperence in him? Will you not stand by him in spite of his flaws? For you are both orphans; and no one deserves to be alone.

Mary was silent for a moment – but she was not deaf to the hat's logic; nor blind to her own loneliness. Her anger began to fade; her conscience began to gnaw at her; she wished she had never held Pavel Paskevich's hand – but it was too late; the deed was already done. Mary was shaken; she did not know whether she could forgive Thomas – but she felt her anger gradually giving way to guilt; she had been unjust, she had driven him to irrational jealousy, she had revealed herself as petty – and she began to feel regret for doing so –

And do you not see, in Thomas Riddle, a vehicle for your own greatness? You are both possessed of prodigious magical talent; together, you will surely accomplish remarkable things –

Mary was stunned. Remarkable things? What could possibly –

The hat abruptly lifted itself from Mary's head; the brightness of the Great Hall was momentarily overpowering . "SLYTHERIN!"

For the interminable trial that was her sorting, the applause was very sparse; Mary wondered whether the hat had vocalised all it had said within her mind, before dismissing such a silly notion; yet it was curious that the Slytherin table had conferred substantial applause upon Eileen Prince, who was a bleary-eyed, runny-nosed, considerably ugly girl, yet dismissive if not contemptuous of Mary, who had all her life commanded adoration everywhere she went.

Mary went to the Slytherin table to sit among Prince and the other already-sorted. None greeted her – they studiously avoided eye contact with her – indeed, Eileen Prince even inched away from her, while the reptilian, curly-haired, smirking Caracallus Lestrange gave her something between a sneer and a leer. Mary probed against the surface of Lestrange's mind and quickly withdrew – he was thinking highly obscene things about her in vivid detail. The boys in Salisbury aged eleven to twelve had carnal thoughts about her as well; but theirs were jumbled and sometimes even endearing, full of confused longing and shame, and invariably banished to the subconscious. Lestrange's lechery was of another sort.

"Riddle, Thomas!"

Thomas approached the stool with perfect, almost comical sangfroid. In four seconds the hat yelled, "SLYTHERIN!"

Mary clapped fervently; the rest of her table, only out of the most perfunctory politeness. Thomas strode to her side and seated himself at her left; their hips brushing together. At once, he seized her wrist again, as if gripped by the fear that she might, at any moment, dart across the hall to the Gryffindor table and into the welcoming arms of Pavel Paskevich. Mary, unperturbed by her brother's possessiveness this time, smiled at him, gently pried his bony hand from her wrist, and clasped it in her own, giving it a tender squeeze.

Thomas regarded her with a quizzical expression, but Mary's smile remained steadfast, and he slowly returned the gesture – though with such force that Mary winced. She would have to teach him how to hold hands like a normal boy.

The other first-year Slytherins observed them with unveiled hostility; Walburga Black's gaze swept over Mary with palpable disgust as she whispered something into the ear of the blonde Condril Parkinson – and Mary, meeting Black's strikingly grey eyes, suddenly understood; Black thought they were muggleborns, and she hated muggleborns; she thought the little scene Tom made during the sorting was obviously symptomatic of their inferior blood; Walburga's uncles, eminent men with eyes similar to hers, told her that muggleborns were abominable creatures, unworthy of magic; and she could not stand the fact that Mary – a muggleborn – was more beautiful than her. Repulsed by Black's thoughts, disenchanted that both her male and female peers had minds so vile, Mary felt a gloom falling upon her – then remembered she had Thomas – whose mind was more fire than lust – whose soul was keep and luminous, a moon covered in incandescent blood.

The sorting ended with a freckly, rather miserly-looking blond boy named William Wilkes being put into Slytherin. He was received with much more applause than Thomas.

Headmaster Armando Dippet, a three-hundred-year old man who would have looked perhaps half that age, if not for his entirely colourless skin, rose from his seat and made a speech. "Esteemèd pupils, venerable professors, and all other entities corporeal and metaphysical, I bid you welcome to another year at Hogwarts School of Witchcraft and Wizardry," he began in a firm voice for one so decrepit. "Ere we attend to the feast, let us salute those many alumnae of our great school who in the bygone year perished fighting in Spain. Whether for Velasco or the Antiguo Ministro, all become brothers and sisters in death."

Mary found beautiful what ensued; the student body, almost in unison, drew their wands and pointed them towards the ceiling. A luminous glow emanated from the tips, hanging suspended in the air for a minute's span, until Dippet lowered his own wand and resumed his discourse. Compared to this luminous interlude, his speech was mundane, and so Mary's attention drifted instead to Thomas's thumb, which was tracing gentle circles on the back of her hand. She marvelled at his gentleness, coming so soon after such brutality, and her mind wandered again to the image of the full moon veiled in glowing blood.

"Without further ado, I bid you eat!" Dippet concluded.

A mountain of food materialised before Mary; she had never seen so much food – nor so many positively mediaeval items thereof, such as a whole roasted piglet rotating by its own volition midair, suspended above a bed of cabbage and grape leaves. Mary looked at Thomas; his eyes were filled with an immense hunger, not just of the body, but of an existence characterised by recurrent hunger – and once again felt tenderness for him. She would nourish him, not just with food, but all the affection he needed; she would fill him; she would make him whole. Thomas, however, thought foremost of making amends for his stupidity on the train; too proud to vocally apologise, he began levitating food not to Mary's plate. Mary watched her twin perform magic with delight – none of the other first years could levitate food without saying, "Wingardium Leviosa" aloud; Thomas did so wordlessly, effortlessly. More than one student gazed at Tom with a mix of admiration and resentment.

"So what are you two," sounded the saccharine voice of Condril Parkinson, "brother and sister? Or boyfriend and girlfriend? Or both?"

That Parkinson's profuse blonde hair was straight along the sides, curly on the back, and glowed ever so slightly on their own accord suggested a magical stylisation and therefore a magical upbringing, while her bold, inquisitorial stare suggested a spoilt one at that. Mary disliked her immediately.

"Brother and sister," Tom replied coolly.

"Really? You sure look more like boyfriend and girlfriend to me. Unless muggle siblings act like that nowadays." Parkinson giggled. "You're twins, aren't you? Just like Pollux and Castor. Did you know that in Ancient Greece, they –"

"Enough, Condril," enunciated a much older boy, adorned with a badge bearing the Slytherin insignia, who had evidently been appointed to supervise the first-years. Handsome, with dark brown hair meticulously parted and a ceremonious demeanour, he reminded Mary in equal measure of her two brothers. "Muggleborns aren't to be bullied, but civilised. If they're in Slytherin, it's because they've got a pureblood ancestor or two. So leave them be; that's an order from a prefect."

"Yes, Arcanius," Parkinson muttered, immediately turning to whisper something into Walburga Black's ear, eliciting a sneer.

Though grateful for Arcanius's intervention, the manner in which he pronounced 'Muggleborn' reminded Mary of how her Uncle Godfrey said 'native' when speaking of his magistrateship in Rhodesia.

8:23pm, 1 September 1938

"You're sleeping on the floor," Caracallus Lestrange sneered, kicking over Tom's suitcase. "Mudbloods don't deserve beds."

That word again – its connotations becoming clearer with each passing moment. Tom, in second-hand robes and with hair untouched either by wand or enchanted comb, was clearly an outsider here. Of course he was; the Slytherin boys' dormitory was nothing short of regal – all gleaming stone and dark wood, plush chairs and green velvet bedding, like the lobby of a mansion for a baron with a predilection for green hues and engraved serpents – everything here was designed to exclude him.

But he would have it all; this luxury, just like Mary and the luxuriousness of her spirit and flesh would soon be his, were already becoming his (Tom soothingly recalled how she held his hand at dinner, of how her tantalisingly soft hip nestled against his own); all would be his. All he had to do was claim it; and so he unsheathed his wand.

Lestrange ruffled his curly mane and chuckled smugly, "Well, lads – seems the mudblood fancies a duel. How many hexes d'you reckon he can parry before he's crying for his mum? Three?"

"Two!" bellowed Alistair Avery, who had claimed a bed by dumping his belongings onto it with little ceremony. He sprawled across it like a bloated toad, one hand patting his profuse belly, the other absent-mindedly scratching at his trousers.

"One," said William Wilkes, from whose small, beady eyes Tom gleaned gleeful anticipation of cruelty to enact upon him, and whose wiry blond hair was styled in a fashion almost identical to Caracallus Lestrange's – though markedly less well-done. "Mudbloods don't fight."

"None. He doesn't even know which end's up," intoned Shalmaneser Nott wisely, as if delivering the verdict of an extensive statistical study. His thick spectacles caught the glow of orange lamplight as he peered at Tom with a look of scorn, adjusting them on his long, pointed nose.

Caracallus Lestrange chuckled in his contended manner again. "Then let's have at it. Hit me with your best hex, mudblood – go on, I bet you've got some real fancy ones." He made an exaggerated gesture towards his face and chest.

Tom stared into Lestrange's conceited eyes, groped for his thoughts, and discovered that Lestrange was a familiar sort. There were a dozen Lestranges at Wool's – a single show of force would be sufficient to wrap him around Tom's little finger. Yet Tom was beset by a latent uneasiness. The other boys in the room weren't just magical, but likely considerably more adept at wielding their magic than Tom. Lestrange and Nott had enchanted their robs to flow aesthetically; at dinner they all spoke of the feats of their wizardly relations, both living and dead. Wilkes had already plastered in front of his bed an animated poster of a vigorous, uniformed man on a broom – conceivably a magical sportsman. Magic to them was as natural as breathing, while Tom was still just learning to inhale. Yet they had relied on incantations for even the simplest magical tasks at dinner – levitating, slicing, heating, cooling – Tom could do all of that silently, and often without his wand. Perhaps he had an edge; that of natural endowment. Virginal dogs sometimes clobbered veterans at the Oaktun mutt pits simply on account of their inborn capacities.

"Hurry up already!" Avery yelled. "You're boring me! Wanker!"

"He can't do it. I told you, Caracallus – mudbloods don't fight," Wilkes said sagely.

Tom glared at these two imbeciles – their minds were feeble and frivolous – before turning to the Lestrange and saying, "Sure, why not?"

Tom's wand was pointed directly at Lestrange's chest, but it would go unused; it was a distraction. The only two spells with offensive capacities Tom knew – he had only a few hours in Diagon Alley to practise – were Incendio and Accio, the latter a dubious proposition with regards to objects as heavy as eleven-year-old boys. Better to eschew them and resort to the Devil in him, Tom thought, with which he had ruled at Wool's for years. And so, with a swift movement of his left forearm and hand, kept cunningly hidden his back until now, Tom sent hurtling the lamp from Shalmaneser Nott's nightstand directly at Lestrange's face.

It shattered loudly, crunched pleasingly; Lestrange fell to the ground, clutching his bloody face, screaming like a lost child.

Suddenly, "Stupefy!" The spell from Wilkes struck Tom's shoulder; weaker than it looked, it nonetheless caused Tom to stumble back and trip over his open, disheveled suitcase.

Tom lay on the floor – Wilkes glared down at him – but Tom was unfazed; even filled with a peculiar joy – the premonition of total triumph. He had won a duel against a pureblood; against a boy who had grown up around magic, and Tom – not even three weeks ago – had never used a wand before. It was just a matter of making the most of his victory parade.

Like a drunken Oaktunian mutt punter, Tom leapt to his feet and tackled William Wilkes. The latter crashed against the wall as Tom pressed his forearm against Wilkes' scrawny neck. Tom was neither taller nor more robust than the ratlike boy, but it was clear he had infinitely more experience in scuffles of a physical nature. It was easy to pin him down; any boy of Wool's, aged eight upwards, could have, provided they were close enough to Wilkes to impede his resorting to wandwork.

"I yield – I yield –" Wilkes cried hoarsely.

Tom relented; a mistake, for in that moment Alistair Avery, twice Tom's bulk, clamped onto him from behind in a bearhug. The air squeezed from his small, emaciated body, Tom flailed violently but to no avail. Wilkes reneged on his vow and began punching Tom. Luckily, the pair's lack of coordination worked in his favour – Tom shook vigorously, and Wilkes' punches often found the wrong target. Tom attempted to bite Wilkes, but the latter evaded; instead, Tom's teeth sank into Avery's fat bicep.

Avery roared, and Tom profited from his newfound freedom to snap his fingers, and send Avery flying backwards into Nott's wardrobe. Then Tom kicked the traitorous Wilkes in the groyne – Wilkes screamed so Tom kicked it again – Tom elbowed Avery in the face – but Avery caught the elbow with his fat paw, and twisted Tom's arm; Tom snapped his fingers again – Avery fell to the ground, Tom raised his leg, and brought his heel down on the back of Avery's fat neck.

All in the room except Tom and Shalmaneser Nott were in varying states of incapacitation – Lestrange continued to whimper; Wilkes and Avery were moaning in pain; Avery's nose was bleeding. Nott, the bookish, anaemic sort that he was, quivered under under his covers, arms shielded over his head like a scared turtle. Grinning, Tom, simply because the opportunity was too good to pass up, yanked Nott by the ankles and tossed him off the bed. Nott hit the ground with a girlish yelp. Tom was already anticipating recounting the night's exploits to Mary, describing how he had single-handedly put all four of his tormentors – who had alternated between ogling and subtly disparaging her during dinner – firmly in their place. He would protect her at Hogwarts, and then forever. Tom would smash lamps into the faces of both Neville Chamberlain and King George if he had to. The blond boy Mary so admired and so desired would have stood no chance against Lestrange alone, let alone Lestrange and his lackeys.

But then, the adrenaline faded, and biting pain coursed through Tom's body at multiple places – Wilkes' blows and Avery's squeezing had not been completely feeble; it had been years since Tom permitted anyone to hit him more than once. He limped slowly towards Lestrange, who had curled into a foetal position – Tom seized the broken lamp – Lestrange howled – Tom, raising his arm, prepared to bring the lamp down on Lestrange's head.

"No, please, stop, Riddle, please – I'm sorry, I'm so sorry –"

Tom's way of showing mercy was to smash the lamp on Lestrange's back instead. Lestrange emitted a pitiful squeal. Annoyed by the noise, Tom spat a mixture of mucus and blood onto the defeated boy, who groaned one last time and then went silent. Tom threw the lamp onto Nott's bed.

Avery was, slouching on his bed, pressing his hand against his profusely bleeding nose and examining it with horror; Wilkes hunched on the floor, clutching his groyne, his expression that of a small child who had just bit into a fresh lemon; Nott was dully repeating 'reparo' at the shattered lamp with a handsome, but only quarter-effective wand movement. Caracallus Lestrange was motionless, save for the slight rise and fall of his chest.

"Anyone else want to call me mudblood?" said Tom.

Silence.

"Good."

Tom turned around, picked up his suitcase, and, finding his bed, began unpacking.