Work Header

The Anatomist

Chapter Text

James Joseph Moriarty was born in Galway, in 1976. His birth certificate no longer exists.

If it did, it would list his father’s name (Dr. Joseph Arthur), his mother’s (Mrs. Elizabeth Anne), and his birth weight (2.7kg). It would not tell you that his eyes were blue, or that he entered this world as he will leave it – howling.

It would not tell you that five minutes later his mother (Mrs. Elizabeth Anne) gave birth to a daughter, his sister. His twin. The records of her birth burned with his, but if they hadn’t, you would know her name.

Mary Elizabeth Moriarty was born in Galway, in 1976.

They will call her Molly.


Their name was not Moriarty, not then. Moriarty is a cipher, a small piece of a larger puzzle; Jim chooses it when they are twelve, after their mother dies and their father is sent away and they become penniless orphans, like in a storybook. He writes the name above the creased fold of a brown paper bag, the nearest paper to hand. His pen shakes, excitement like a flame behind his eyes.

Jim and Molly Moriarty, he writes, with long, heavy loops on the l’s and y’s. She takes the biro and copies it out carefully, her handwriting small and neat and utterly unremarkable. Jim and Molly Moriarty, she writes, over and over again, covering the wrinkled brown paper with their new name, and when Jim takes it from her the ink smears under his fingers.

This is what we really are, his smile says. This is what we become.

They will use many other names. This is the only one they remember.


Their father is a professor of mathematics at Trinity, and when he swings Molly into his arms at the end of the day she tastes the chalk dust on his clothes, like desert sand under her tongue. Sometimes she sneezes into his collar, and he laughs.

“Hello, my little mouse,” he says, whispers into her ear before scooping Jim up in his other arm and spinning them close, in a tight circle down the length of the hall. Their mother looks on from the doorframe, her tired face fond.

(Jim doesn’t like to be spun, doesn’t like to be carried or embraced or confined, but he’s good at pretending. Only Molly can see the edge to his smile.)

“Now then,” her father says, a child on each hip, “what does the little mouse want for supper?”

“Cheese,” Molly answers, quite seriously. “Mice eat cheese.”

“And chocolate biscuits,” Jim adds with a charming, gap-toothed grin. “Mice go mad for chocolate biscuits.” Her parents laugh, but Molly doesn’t understand why. Mice will eat anything, she thinks, that’s why they’re pests. Her mother sets traps and everything.

“Don’t frown, little mouse,” her father says, kissing her cheek. “You’ll get your cheese.”

“Will it be in a trap?” Molly asks, picturing the small, furry bodies and their small, snapped necks. She’s seen them in the traps, still twitching.

Her parents laugh again, their eyes flashing in the lamplight.

Molly likes making them laugh; she’d like an answer to her question more.


Molly has soft, mouse-brown hair that curls around her ears, rarely tangling. She is small for her age, with quick-pale fingers and a quiet, nervous disposition, and she hides in linen cupboards, under tables and behind dust-heavy curtains. She learns not to sneeze.

People think Jim is the clever one, and he is clever. He always knows just what to say and just how to say it, and when their father’s friends from the university come to dinner they watch Jim’s proofs and equations unfold with awe in their whiskey-fogged eyes.

Impressive, they say. Remarkable. The word prodigy gets thrown around quite a bit, though Molly had solved the same equations that afternoon after school, and she’d shown her work.

But Molly hides from guests, from teachers, from her mother and her father. She doesn’t hide from Jim, because he will always find her, and because he doesn’t like having to look. If she tries he will crowd in beside her, too large and too warm and breathing too loud, his knees sharp against her side, and he will say, “If you ever run away from me again, little mouse, I’ll pinch you until your arm turns blue.”

“If you ever turn my arm blue,” she whispers back, “I’ll bite your fingers off.”

Yum,” Jim says, smacking his lips, and then their mother finds them, laughing like jackals in the darkness at the depths of the broom cupboard.


Molly is eight years old when she sees her first human corpse.

She’s hiding in the narrow space beneath the stairs when the kitchen door creaks open, filling the hall with the midnight summer smells of the alley outside. Two man-shaped shadows walk in, their footsteps loud in the sleep-silent house. The second shadow has her father’s neat beard and narrow shoulders; the first is taller, broader in the waist and chest.

Her father flicks on the kitchen light, and Molly sees the knife in his hand.

Fuck, Joe,” the broad man says, his voice shaking. He has red hair and a dark red beard and a red, flushed face. He watches the knife, his eyes wide and white with fear. “I don’t know what they told you, but it weren’t me that nicked it, I swear. I know better than to take what isn’t mine.”

Her father’s smile has a familiar edge. “An interesting defence, for a thief.”

“I don’t steal from you,” the broad man says, close to tears. “You know I don’t.”

“Yes,” her father says, not unkindly. “I do.” He takes a step closer to the broad man, and Molly watches as his grip on the knife changes. Tightens. “But unfortunately for us, Mike, the rest of the city lacks our nuanced grasp of the situation. They think you got the better of me. They think you won. And that’s not something I can let them think for long.”

Her father’s knife slides neatly into the broad man’s belly, splitting him open from stomach to sternum. The man spills across the kitchen floor, collapsing in a sudden deluge of dark blood and the darker, splattering shadows of his intestines. It takes him a moment to die (shuddering silently like a mouse in a trap) and Molly meets his eyes, just before the light in them dims.

Her father stands over the body, watching the blood flow over the white linoleum. It touches the toes of his shoes. “Molly, come here.”

She crawls out from beneath the stairs and walks into the kitchen. The floor is cool against her bare feet; she buries her hands in the pockets of her dressing gown. Her father sits at the kitchen table, sets the knife down beside the fruit bowl, and lifts her into his lap.

“So,” he says, his blood-soaked sleeve damp against her ribs as he holds her close. “What’s a little mouse doing out of bed at an hour like this?”

“I couldn’t sleep,” Molly says. She frowns at the body on the floor. “Why didn’t he try to stop you? He was bigger and stronger.”

“Such a good question,” her father says, and drops a kiss on the top of her head. “What do you think, Mol? Why couldn’t he stop me?”

She thinks hard, remembering the look on the man’s face when the light flicked on and he first saw the knife. The way his hands shook as he held them out in futile supplication. Her eyes fix on the broad man’s body, on the growing emptiness inside him.

(She never imagined we could contain so much. She wants to see more.)

“He was afraid of you,” she says finally. “Not afraid of the knife, or of getting hurt, or even of dying – he was afraid of you.” She turns to meet his eyes. “Am I right?”

“My little prodigy,” her father says, and tucks a loose strand of hair behind her ear.


That autumn, Jim starts bringing her dead birds.

“I could save one of the live ones for you, if you want,” he says, which is uncharacteristically generous of him. (Jim will never really learn how to share.) “They’re a lot more fun.”

Molly shakes her head and snaps on a pair of plastic gloves. “I learn more from them when they’re already dead,” she says. She holds out her hand. “Scalpel.”

Jim passes her a sharpened kitchen knife. “I’ve been thinking about trying for a cat.”

Molly pauses, her knife poised above the wren’s still chest. “That would be interesting. A cat’s anatomy would be a lot more like the real thing than a bird’s.”

Jim leans over her makeshift autopsy table, propping his chin up on his hands. He grins at her. “Also, cats can scream.”

Molly frowns. “Birds can’t scream?”

“I’ve never heard one, and not for lack of trying.”

“I wonder,” Molly says, and moves the tip of her knife to the wren’s throat.


The first time Jim tries to kill her, it is a week after their eleventh birthday.

They are upstairs, sprawled across the landing of their long, narrow house and working through the problem set their father had passed them that morning at the kitchen table, over toast. Afternoon sun streams in through the windows, catching dust.

Jim lies on his stomach, his chin resting on the edge of his open notebook. “I’m done,” he trills. “I finished first.” He tilts his head to the side, looking up at her. “I always finish first, have you noticed?”

Molly looks down at his work. “Actually, I haven’t.” She points with the sharpened end of her pencil. “This is wrong. You rushed through it; I can tell.”

He slaps her across the face, hard enough to stun her for a moment while he twists his fingers into her hair and drags her to the edge of the landing. “I’m not wrong,” he says, and pushes her down the stairs.

She fractures her right leg and dislocates her shoulder. She tells the doctor that she tripped over the rug and fell, that she was clumsy and it was her own stupid fault. She laughs with him, like it’s just a joke with a painful punch line.

Her father can see through lies like other men see through glass. He stands by her side, one hand on Jim’s shoulder, the other on hers. He doesn’t contradict her story.

That night Jim sleeps in a chair beside her bed, the crown of his head against her hip. “I don’t know how I’d live without you, Mol,” he says, to the dark. “I don’t know how I’d breathe.”

“With your lungs, probably,” Molly says, and reaches past the pain in her arm to link her fingers through his.


Four months later, Jim is halfway through a story about yesterday’s rubbish football match when his speech begins to slur.

“Something’s wrong,” he murmurs, mumbles, spits, his head in his hands and his eyes open wide, staring at the air before him in fear and horror and (delicious) surprise. “Mol,” he says, “something’s wrong, I can’t see—”

It starts with slurred speech and blurred vision and the sudden droop of his left eyelid, and the doctors say stroke and neuromuscular disease and descending paralysis before they stick needles in his spine and tack pictures of his brain to the wall. They mutter together in soft voices like cattle lowing in open pastures, and her parents’ knuckles grip white with fear.

The next morning, Jim can’t lift his arms.

“It’ll be your legs next,” Molly tells him, when the adults finally leave them alone in his hospital room. (“Poor dears,” one of the doctors says, “they seem very close,” and her father covers his mouth as he nods.) She sits high on the edge of his bed, her legs crossed at the ankles, her hands in her lap. “It’ll be your legs, then your abdomen, then your lungs. You’ll suffocate, probably.”

Jim tries to grin at her, but his lips twist strangely, to the side. “Poison,” he slurs, his exhale like a laugh. “How like a girl.”

“I think,” she says, “that I’ll take that as a compliment.” She swings her good leg back and forth, out and in, and the hospital bed creaks beneath her. “I slipped a small dose of botulinum toxin into your juice. I could teach you how to make it, if you want.”

He gives her a weak nod, and she smiles, bending down to drop a kiss on his forehead.

Molly tells the doctors about a funny-shaped tin of beans she’d found behind the supermarket, a tin Jim had eaten from on a dare. One botulism antiserum and five long weeks of recovery later, Jim is strong enough to walk again.

She lends him her crutches.


They don’t mention the poisoning again until university.

“What if I hadn’t figured it out?” he asks one evening, over a curry. He has sauce on his chin; she wipes it away with a neat swipe of her thumb. “What if I hadn’t known it was you?”

She shrugs. Wipes her thumb on the tablecloth. “Then you would have died. That was the whole point of the exercise.”

She never doubts that he loves her. In moments like these, she can see it written in his eyes.


When they are twelve, their mother goes down to the kitchen in the middle of the night, puts the kettle on for tea, and shoots herself in the head.

Molly has never seen her father cry before; he pushes them back, out of the kitchen, away from the blood spilling slowly across the white linoleum floor. Most of her mother’s face is missing, is spread across cabinets and clean dishes and the rug at the foot of the sink. Her father tries to cover their eyes, to turn them away.

“No,” she says, her fingers fisted in his shirt. “No, I want to see—”

The teakettle whistles.


The day before she died, their mother turned over enough evidence to the Garda to send their father to prison for the rest of his life. They take him from the house not long before dawn, his hands cuffed behind his back. His shoes leave bloody footprints in the hall.

“I’m glad she’s dead,” Jim says, sitting on the stairs, Molly’s hand clutched in his. “I wish she’d died slower.”

The gardaí are taking their house apart, piece-by-piece. Searching for evidence. Preserving the crime scene. One garda looks up from his camera and gives them a stunned, unsettled look; he heard.

“My brother’s in shock,” Molly says in a choked, teary voice. “Has anyone talked to our grandmother? I don’t think he’ll leave with anyone but her.”

“I-I’ll go check for you,” the man says, and flees to the still-bloody scene in the kitchen. Molly twists Jim’s fingers hard between hers, and he hisses in pain.

“The hell—”

“You need to learn to shut up,” she says, and curls into his side, her head resting on the sharp bones of his shoulder. The air in the house smells sickly-sweet, thick with the stink of strangers and mud from the street outside; she buries her nose in Jim’s collar, breathes in laundry soap and boy. “We have to be invisible,” she says, to his throat. “We have to disappear.”

His arm draws tight around her shoulders. “Or what?”

Or they’ll catch us, she thinks, and closes her eyes against a camera’s flash.


One week before the explosion in Baker Street, Molly asks Jim what he remembers about their mother.

“An odd question,” he drawls, lounging in his chair with his arm draped over the stiff-plastic back. It’s meant to be their first date, a quick lunch in the hospital canteen and the opening act of the ridiculous little psychodrama Jim’s staged for the benefit of his favourite nemesis. His posture is all wrong, out of character and out of place; Molly wants to kick him in the shins.

Instead she takes a bite of her salad. “We don’t have to talk about it,” she says, innocently. “Not if it upsets you.”

He leans forward, his eyes narrowed. “It doesn’t upset me.”

She shrugs. “All right.”

“It doesn’t.” He gives her a forced, flirtatious grin. To their co-workers at the next table, it probably seems perfectly charming; up close it looks like a grimace. “I remember that she did the crossword in the paper every morning, in ink. I remember that she chewed peppermints after dinner. I remember that she wore her hair long, like yours, and then I remember that she betrayed our father and shot herself in the fucking face before he could do it for her.”

Molly nods. “That’s what I remember, too,” she says, and kicks him gently under the table.


They leave Ireland the day after their mother’s funeral.

Their grandmother’s house in Brighton is wide windows and deep carpets and pale trim, and the distant sound of the sea keeps Molly awake and red-eyed for the first year. It is never home.

But she finds that there are just as many places to hide in Brighton as there were in Dublin (behind books, behind schoolwork, behind a smile) and she adjusts. Slowly.

Jim does not.

He has never been anything but universally adored, but now the boys at school call him poof and freak and pitch their voices high and lilting to mimic and mock and they have no idea, he says, no fucking idea what he could do to them. What he’s done before.

That spring, four cats and one dog go missing in their neighborhood. Molly and Jim help in the search, stapling lost: reward signs to telephone poles and community boards. Jim smiles all the while, and their gran calls him a good, sweet boy.

Molly learns a lot that first year in Brighton.


The chair beside her creaks. “Are you really reading that?” a deep voice asks, and Molly squeaks in surprise, her head snapping up from her book.

A tall, fair-haired boy sits beside her, his arms folded in front of him on the library table. He’s familiar, two years above her and popular despite his awkward height and slightly spotty face. His expression is sheepish.

“Sorry,” the boy says. “Didn’t mean to startle you.”

“No, it’s fine,” she says, her hands fluttering to her lap. “It’s just – people don’t usually notice me. In the library, I mean. When I’m reading.” She blinks at him. “What did you say?”

The boy smiles. “I asked about your book.” He leans close, his shoulder almost brushing hers. He frowns at the diagram on the open page. “Is that meant to be a heart?”

“A spleen, actually.” Off his puzzled look she adds: “Not a very healthy one.”

“Oh. Cool.” He sits back a little, and she starts to breathe again. He smells like chlorine and stale crisps, and her heartbeat thunders in her ears. He asks a question; she doesn’t hear it.

“Sorry?” Molly says, and the boy laughs.

“I said, do you want to be a doctor?”

“Oh, yes,” she says. “Well, a forensic pathologist, really. They cut up dead people and find out how they died.” She bites her lip. “That sounds weird, doesn’t it? That sounds really weird.”

“No, it sounds brilliant. Creepy, but brilliant.” He looks down at the spleen again, his long, friendly face suddenly shy. “I notice you.”


“You read here every day after classes. Mostly medical books, or maths, but sometimes you play chess with your brother. I think you usually let him win, just to avoid the fit he throws when he loses.” His mouth quirks at the corner. A small, self-mocking half-smile. “You said no one notices you, but I do. I notice.”

“Oh,” she says, stunned. “I—”

“My name is Carl,” the boy says. “Carl Powers.”

“I’m Molly,” she breathes, already lost in love.


Twenty-one years later, she walks into the lab at Barts and sees Carl’s trainers sitting on the table, next to Sherlock’s microscope. They still have Sussex dirt caked on the soles.

(Jim’s hand settles soft between her shoulder blades, and she smiles around the word romance.)


Carl kisses her for the first time on the front steps of her grandmother’s house. She has sand in her shoes, between her toes, and his mouth tastes like salt. Like chips and the sea.

“Can I?” he says, and she nods, quickly, arching up to meet him as he bends and it’s a bit awful at first, in a wonderful way. His mouth is too big, or hers is too small, and she would disappear into the ground, if she could. But then his hand cups the back of her head, long, steadying fingers and his face above hers and her heart breaks for him, a little.

He’s a sloppy kisser. She doesn’t mind.

“Well now,” Jim says from the open door, his voice high and cutting and oh-so-amused. “Isn’t this a pretty picture?”

The kiss ends, abruptly. Molly doesn’t open her eyes. “Carl,” she says. “You know my brother Jim.”

“Uh, yeah,” Carl says, and she can tell by his voice that he’s one of the boys from school, one of the boys who call Jim queer and pour spoilt milk into his gym bag. He takes a step away from her, his arms hanging awkwardly at his sides. “Hey, mate.”

Jim gives the other boy a long, pitiless look. “How very nice to see you again, Carl,” he says, and for a moment he makes no effort to hide the emptiness in his eyes. Carl flinches, and Jim’s lips twist in a wide, hollow smile. “Mol, you’re late for tea. Gran’s waiting.”

“I’d better go,” Carl says, and takes a stumbling step backward. “I’d better – I’ll see you Monday, Molly. At the library?”

“The library,” Molly agrees, and then he’s gone, down the steps, onto the pavement, and away. Jim wraps his arms around her waist from behind, his chin resting on her shoulder. Together, they watch Carl go.

“I bet you’d like to cut him open,” Jim says, his breath warm against her ear. “I bet you’d like to see inside.”

She folds her hands over his. “I bet you’d like to watch.”

He laughs. “My little mouse,” he says. “You know me so well.”

Their grandmother calls, and they go inside for tea.


The day Carl drowns in a London pool, Molly watches the tournament from the sidelines. Her throat is sore with the thick taste of chlorine, her voice hoarse from cheering. She has their lunches in a brown paper bag, sandwiches and crisps and two still-cold cans of ginger beer. She clutches it to her chest as she shouts, rises to her toes to see over the crowd and cries faster, Carl, you can do it. I know you can.

He jerks in the water, and for an odd, weightless moment she thinks he’s heard her, thinks he’s about to lift his head from the water and reply. Then he jerks again, and is still.

He’s dead by the time they pull him from the water. His head lolls gently to one side, and she looks into his open, sightless eyes. His left eyelid droops, slightly.

The bottle of eczema medication is still in his locker, tucked into one of his trainers. She takes them both – dumps their lunch into the bin and hides the trainers in the paper bag. They fit neatly under her arm as she slips back into the crowd.

Jim always forgets the details.


“It has to be done,” Jim says, twenty-one years later. His forehead touches hers, and their breath mingles. “He’s too close. He sees too much.”

“He doesn’t see me,” Molly says, as if she thinks that might be enough to keep him safe.

It isn’t.


Two days after Carl dies, Molly skives off school and takes the train back to London.

The pool is not a crime scene. (Tragic accident, the papers say, and no one disagrees.) Her footsteps echo on the tile as she walks, the soft sounds of the filters loud in the silence. She crouches by the edge, and her fingers brush the water, rippling the light beneath.

“No, listen to me,” a boy’s voice says from the corridor outside. She hears two sets of quick, steady footsteps, coming closer. “Powers had no history of seizures or neuromuscular disorders; he was in perfect health, aside from his skin condition and a mild case of gastroparesis. These facts, coupled with the as-yet-unexplained disappearance of the boy’s shoes—”

“Look, kid,” a man’s voice says, and two silhouettes appear in the frosted glass of the pool door: one short and heavy-set, the other tall and long-limbed. The man clears his throat. “Did you know Carl Powers?”

“No, of course not,” the boy says, crisply. “I read about him in the papers.”

The man rubs his hand over his forehead, his posture weary and long-suffering. “Then you read that we have no reason to suspect foul play. Carl Powers’ death was a tragic accident.”

“Tragedy is not an explanation, Detective Inspector – it’s empty sentiment disguised as analysis.”

“That may be,” the man says, “but in the end it’s all we’ve got.” He gives the boy a paternal pat on the shoulder; the boy just barely stops himself from flinching away. “I’ve real work to do, kid. Don’t bother me again.”

The man walks away. The boy waits unmoving until his footsteps fade down the corridor, then he turns abruptly and pushes through the door into the echoing silence of the pool. His eyes fix on hers.

“I know you’re not a student here,” the boy says. “Don’t bother lying about it.”

He’s tall, sharp-boned and scarecrow thin – a sudden growth spurt in the last two months, she thinks, and his voice hasn’t quite finished changing so he can’t be more than a year older than she is. His hair is dark, curling, and a little too long; his clothes are well made, expensive but treated casually – he’s burnt a small hole in his left sleeve and there are spatterings of chemical stains on his right. Add in the posh accent, and he may as well have the words public school swot written on his forehead in ink.

“You’re right,” Molly says. “I’m not a student here.” She sits at the edge of the pool, hugging her knees to her chest. “Neither are you, though.”

He frowns. Walks around her, his hands in his coat pockets. “You’re not from London. I’d say Sussex, judging by the length of your vowels, with a faint yet unmistakable Dublin undertone. But you haven’t lived in England long – you’ve shed your accent deliberately.”

“Your shoes are too tight,” she says, “and they pinch at the toes. You’ve outgrown them already. Probably your second pair this month.”

He stops walking. “You knew Carl Powers.”

“Yes,” she says. “He was my boyfriend.”

An odd, focussed expression passes over his long face. “I’m sorry for your loss,” he says with great concentration, like it’s something he learnt from a phrasebook he bought before travelling to a foreign country.

I’m fascinated by the customs of your people, Molly thinks, a little hysterically, and starts to giggle.

The boy stiffens. “Did I say something funny?”

“No, no, sorry,” she says, and lets out one last little hiccupping laugh. “I just – it’s an odd thing, grief. Hits you in unexpected ways.” She stands, rubbing at her eyes as if she’s been crying. (She hasn’t. If she does, Jim will know.) “You don’t really think someone hurt Carl on purpose?”

His head tips to one side. “Don’t you?”

The boy’s eyes are cold and pale and their pull is like gravity (like the tide tempting her to sea) but Molly has always been able to lie, when it matters. She folds her hands into her sleeves and gives him a carefully fragile smile. “He was just a normal kid,” she says. “Why would someone want to kill him?”

The boy sniffs and turns away; she’s lost his attention. “Why is only useful,” he says, “when it leads you to how.”

You’re wrong, she wants to say, and more than that she wants his eyes on hers again, wants to be the focus of his gaze and the diamond-sharp scalpel of his mind. She wants to know what he’d see, inside.

(She thinks she would stop hiding, for him. If he ever bothered to look.)

“Oh,” she says in a small, startled voice, like the sound a mouse makes just before the trap snaps shut, “I should go. I’m going to miss my train.”

He frowns, his gaze turning briefly inward. She can almost see the timetable reflected in his eyes. “You already have,” he says, and walks away. The pool door swings shut behind him.

She’ll spend the next nineteen years wishing she’d asked his name.