Platform 9¾ — An AI-Built 1971 Wizarding-World Roleplay (Four Boys, One Compartment)
Final Product: Platform 9¾
Cover
The 16:9 key-art cover: a dark wood-panelled corridor on the 1971 express, one compartment door half open and spilling gold across the floor. Inside, four eleven-year-old boys are already arguing, already claiming each other — one standing on the seat, one leaning into the window light, one half-asleep, one small and uncertain — while a grey owl watches from its brass cage and a battered trunk waits in the corridor. The viewer stands outside the door as the unplanned fifth friend. Painted for this story in the world's own semi-realistic painterly art direction with GPT Image 2.
Gameplay
The live roleplay exactly as it loads at the share link, captured at 1280×800: the title over a darkened crop of the key art, the one-line premise — '1 September 1971: an eleven-year-old walks the corridor of the Hogwarts Express and steps into the compartment where four boys are meeting for the first time' — the Act-as control set to Creator, and Start Adventure waiting below. Nothing to install; the whole story runs in the browser.
Gameplay
The live setup screen with the Act-as selector open. Platform 9¾ has no pre-written heroine and no fixed player character: Creator is the only role card the story needs, because the fifth friend is built from what you say, who you sit beside and what you refuse to admit before the Sorting.
Gameplay
The optional first-input field, expanded before the run begins: 'You decide how the story begins…'. Walk the corridor with your own opening line — knock, linger outside the door, ask who is winning the dragon argument, or say nothing and let James spot you first — or leave it blank and let the agent open the scene. Whatever you write becomes the first beat the live narrative engine answers.
Platform 9¾ is a playable 1971 coming-of-age roleplay about the hour before everything changes — five eleven-year-olds in one train compartment, and a friendship that will decide who all of them become.
It is 1 September 1971. You are eleven, your trunk is too heavy, and the corridor of the express is loud with other people's families. Through a half-open door you can hear an argument about dragons. James Potter is standing on the seat, arms full of sweets, absolutely certain he is right. Sirius Black is leaning by the window with the bored, sharp look of a boy who has already decided to disappoint someone. Remus Lupin is asleep in the corner, pale and worn thin, and Peter Pettigrew is trying to take up less room than he does. James sees you in the corridor and grins like he has found the last piece of something: “You! Perfect timing. Settle this.”
The player is the unplanned fifth. Not a chosen one, not a tag-along — the person the group did not know it was missing. Sit with James and be adopted before Hogsmeade. Sit quietly beside Remus and start reading the secret he would die before telling. Match Sirius's testing and discover why the Black name makes him go cold. Answer Peter honestly and become the first person who ever made him feel kept. Every choice writes a different first hour: who you trust, what you notice, which thread you pull, and what you are afraid the Sorting Hat will see in you.
Three threads run under the small talk and the sweets. The pale boy's secret — why Remus looks ill, why he knows the moon's phase without looking outside, why he says he is not sure the school will want him. The name Sirius runs from — the cold-faced older girl at the door, the pure-blood dynasty waiting at home, the rebellion he has not said out loud. What the hat decides — four boys certain of their houses, one boy afraid of being turned away entirely, and a public choice that will set the shape of the year. Clues, actions, discoveries, reveals and consequences change the ending you can reach.
The scene opens on the train and closes in the Great Hall, and the AI never lets anyone speak like a legend they have not become yet. These boys do not know their futures. They know sweets, dares, house bets and the terrifying question of where they belong. Play Platform 9¾ →
Game Features
- Live LLM Narrative Direction — nothing here is a fixed script. A deepseek-v4-flash agent reads your action, keeps four very different eleven-year-olds in voice, and writes the next beat, the subtext and the available moves as you play. The same agent built the premise, the relationship graph, the three investigable threads and the 'never let them speak like legends' rule from a single world prompt.
- Four Friends, Four Wants, No Interchangeable Voices — James is loud, warm and allergic to losing; Sirius is sharp, reckless and already furious at his family; Remus is gentle, watchful and guarding a secret that could end his place at school; Peter is eager, anxious and terrified of being the one nobody wants. The agent holds each voice separately, so the boy who comforts you is never the boy who tests you.
- Three Investigable Threads — <em>The pale boy's secret</em> (the tiredness, the scar at his collar, the moon he never has to look up), <em>The name Sirius runs from</em> (the older girl at the door, the pure-blood expectations, the rebellion he has not admitted) and <em>What the hat decides</em> (four certainties, one fear, and a public choice that binds or splits the group). Each carries its own clues, actions, discoveries, reveals and consequences.
- Answer In Your Own Words — Or Take The Offered Beat — type any action into the free-text box, or take the Continue beat the scene offers. Hand James the last Chocolate Frog, ask Remus if he is all right, tell Sirius the window seat is taken, or admit to Peter that you are nervous too. Every choice lands differently, and the group remembers what you chose — including every confidence you kept.
- A First Hour With Real Stakes — who you sit with changes who talks to you; what you notice changes what you can prove; what you say at the Sorting changes which friendships survive the hall. There is no countdown and no forced confession — only the small, irreversible physics of eleven-year-olds deciding who they are in front of each other.
- A 1971 World That Keeps Its Own Secrets — no future knowledge, no knowing winks, no borrowed legend. The story stays inside the train, the corridor, the compartment and the Great Hall, with period sweets, house bets, steam, nerves and a castle still enormous and unexplained. The player is genuinely wanted — and every secret, dare and question should cost or gain something.
Character Sprites
Sprite
James Potter, the boy who decides the group exists: messy jet-black hair that sticks up at the back, round wire spectacles, a confident grin, school robes open over a knitted jumper, both arms full of every sweet the trolley carried. He collects friends the way other boys collect cards — with charm, daring and a stubborn refusal to lose. Cut out with BiRefNet into a true transparent PNG so he composites cleanly over the corridor, the compartment or the Great Hall.
Sprite
Sirius Black, heir to a name he already despises: shoulder-length black hair, pale sharp features, grey eyes and a half-smile that is equal parts challenge and armor. Dark jumper, loosened tie, the posture of a boy who sits like he owns the compartment and glares like he wishes he didn't exist. Cut out with BiRefNet into a transparent PNG for the window seat, the corridor confrontation and the Sorting.
Sprite
Remus Lupin, the quiet boy in the corner: light brown hair, a tired gentle face, faint old scars, a patched oversized coat and the watchfulness of someone braced for the worst from every new person. He is the group's conscience and its secret — the one who notices the quiet things about you and says nothing. Cut out with BiRefNet into a true transparent PNG for the compartment and the corridor at night.
Sprite
Peter Pettigrew, small and round-faced and desperate to be kept: mousy brown hair, a nervous half-smile, a slightly-too-small jumper and robes he seems to be trying to disappear inside. He agrees first, laughs nervously, and would rather be the shadow of greatness than himself — but his devotion is real. Cut out with BiRefNet into a transparent PNG for the compartment bench and the Great Hall line.
Production Process Breakdown
Stage 1: World Buildingdeepseek-v4-flash
The world 'Untitled World' began with one line — 'James potter, Remus lupin, Sirius black and Peter perigee meeting on the hogwarts express for their first first time in their first year' — and the AI built the house art direction from it: Semi-Realistic Painterly, a semi-realistic digital painting style with continuous volume, rich mid-tones, controlled soft and hard edges, atmospheric earth colours, dramatic light and visible brushwork. Four character atoms were written as canon: James Potter, Sirius Black, Remus Lupin and Peter Pettigrew, each with a first-sight description, background, wants and a role on the train.
The world 'Untitled World' began with one line — 'James potter, Remus lupin, Sirius black and Peter perigee meeting on the hogwarts express for their first first time in their first year' — and the AI built the house art direction from it: Semi-Realistic Painterly, a semi-realistic digital painting style with continuous volume, rich mid-tones, controlled soft and hard edges, atmospheric earth colours, dramatic light and visible brushwork. Four character atoms were written as canon: James Potter, Sirius Black, Remus Lupin and Peter Pettigrew, each with a first-sight description, background, wants and a role on the train.
Stage 2: Roleplay & Story Draftingdeepseek-v4-flash
From that premise the agent wrote the playable spine: the 1 September 1971 opening, the core conflict of four boys becoming friends in the hour before their lives pull them apart, the relationship graph (James's instant claim on the player, Sirius's challenge, Remus's watchfulness, Peter's dependence), three investigable threads with clues, actions, discoveries, reveals and consequences, four story locations — Platform 9¾, the corridor, the compartment and the Great Hall at Sorting — plus four opening hooks and five story directions. The direction rule was explicit: never let them speak like characters in a legend; let sweets, dares and small talk breathe.
From that premise the agent wrote the playable spine: the 1 September 1971 opening, the core conflict of four boys becoming friends in the hour before their lives pull them apart, the relationship graph (James's instant claim on the player, Sirius's challenge, Remus's watchfulness, Peter's dependence), three investigable threads with clues, actions, discoveries, reveals and consequences, four story locations — Platform 9¾, the corridor, the compartment and the Great Hall at Sorting — plus four opening hooks and five story directions. The direction rule was explicit: never let them speak like characters in a legend; let sweets, dares and small talk breathe.
Stage 3: Character Portrait Artgpt-image-2
The four boys were painted as character cards in the world's own semi-realistic painterly direction — James with his arms full of sweets and a grin that has already decided you are friends; Sirius in dark knitwear with the Black family bone structure; Remus patched and tired and watchful; Peter small, round-faced and eager. Each portrait keeps one consistent, believable face so the same boy can appear in the corridor, the compartment and the hall.
The four boys were painted as character cards in the world's own semi-realistic painterly direction — James with his arms full of sweets and a grin that has already decided you are friends; Sirius in dark knitwear with the Black family bone structure; Remus patched and tired and watchful; Peter small, round-faced and eager. Each portrait keeps one consistent, believable face so the same boy can appear in the corridor, the compartment and the hall.
Stage 4: Three-View Reference Sheetsgpt-image-2
Every character was then locked into a professional three-view sheet on a plain white studio background — front, three-quarter and back, plus a large face close-up — with age, hair, build, clothing and signature props described in the prompt. These sheets are the visual contract: James's spectacles and messy hair, Sirius's shoulder-length black hair and sharp features, Remus's scars and patched cardigan, Peter's round face and too-small jumper.
Every character was then locked into a professional three-view sheet on a plain white studio background — front, three-quarter and back, plus a large face close-up — with age, hair, build, clothing and signature props described in the prompt. These sheets are the visual contract: James's spectacles and messy hair, Sirius's shoulder-length black hair and sharp features, Remus's scars and patched cardigan, Peter's round face and too-small jumper.
Stage 5: Scene Art & Key Artgpt-image-2
The train was painted as a place you can stand in: the empty compartment with its window full of English countryside, the wood-panelled corridor with steam and an owl in a brass cage, the hidden platform behind the brick archway, and the candlelit Great Hall at Sorting. The 16:9 cover then put the camera in the corridor — the viewer outside the half-open door, the four boys already inside — so the key art states the premise without a single word of text.
The train was painted as a place you can stand in: the empty compartment with its window full of English countryside, the wood-panelled corridor with steam and an owl in a brass cage, the hidden platform behind the brick archway, and the candlelit Great Hall at Sorting. The 16:9 cover then put the camera in the corridor — the viewer outside the half-open door, the four boys already inside — so the key art states the premise without a single word of text.
Stage 6: Cut-Outs, QA & Publishingbirefnet-general
The four portraits were cut out with BiRefNet into true transparent PNGs and checked over the corridor, compartment and hall plates. The live share page was captured at 1280×800 across the opening screen, the Act-as selector and the optional first-input field; the studio was captured in three distinct views. Everything was assembled into this page with the world's own prompts, real scene art and the correct share link.
The four portraits were cut out with BiRefNet into true transparent PNGs and checked over the corridor, compartment and hall plates. The live share page was captured at 1280×800 across the opening screen, the Act-as selector and the optional first-input field; the studio was captured in three distinct views. Everything was assembled into this page with the world's own prompts, real scene art and the correct share link.
Scene Backgrounds
BG
The compartment — the heart of the roleplay. Worn blue seats, a brass luggage rack, a coat flung up top and a window full of sunlit English fields. On 1 September 1971 this is where the five meet, where the sweets are divided, where Remus's secret is almost visible and where the friendships that define the year are made or missed. 16:9 plate cropped from the world's own scene art.
BG
The corridor — the space between compartments, where you overhear and are overheard, where you decide whether to knock or keep walking. Steam drifts past the windows, an owl blinks from its brass cage, and the green seat by the door is the last place to sit alone before James spots you. 16:9 plate cropped from the world's own corridor scene.
BG
Platform 9¾ — the threshold. A hidden platform behind a brick archway, a crimson locomotive breathing steam under the iron canopy, brass trolleys stacked with trunks, wet cobbles holding the lamplight. It is the last goodbye to the world you came from and the last chance to stay behind — and the story begins the moment you choose the train. 16:9 plate painted for this world with GPT Image 2.
BG
The Great Hall at Sorting — the public verdict. Hundreds of candles float above four long tables, the enchanted ceiling holds a night sky, and a worn pointed hat waits on a stool at the front. This is where each of the five chooses, in front of everyone, who they mean to be from then on — and where house lines will separate or bind them for years. 16:9 plate painted for this world with GPT Image 2.
Asset Prompts
World Seed & House Styledeepseek-v4-flash
"James potter, Remus lupin, Sirius black and Peter perigee meeting on the hogwarts express for their first first time in their first year" — the exact world seed prompt. The house style attached to every generation: "Semi-realistic digital painting, shaping believable form with continuous volume, color mid-tones, and controlled soft/hard edges. Build form with complete continuous volume, weight, contact, and clear planar turns… Keep rich mid-tones, color shadow, and complete but controlled light-dark steps. Preserve established age, body type, facial features, hairstyle, clothing structure, signature colors, and props."
"James potter, Remus lupin, Sirius black and Peter perigee meeting on the hogwarts express for their first first time in their first year" — the exact world seed prompt. The house style attached to every generation: "Semi-realistic digital painting, shaping believable form with continuous volume, color mid-tones, and controlled soft/hard edges. Build form with complete continuous volume, weight, contact, and clear planar turns… Keep rich mid-tones, color shadow, and complete but controlled light-dark steps. Preserve established age, body type, facial features, hairstyle, clothing structure, signature colors, and props."
James Potter — Three-View Promptgpt-image-2
"Professional character reference sheet on a plain seamless white studio background, soft even lighting: three full-body views of the same boy arranged side by side from left to right — front view, three-quarter view, back view — with one large face close-up portrait at the far right. The boy is an eleven-year-old British schoolboy with very messy jet-black hair sticking up at the back, hazel eyes behind round wire glasses, a confident cheeky grin, wearing a rumpled navy knitted jumper over a white collared shirt and grey school trousers. Photorealistic, detailed skin and fabric texture, sharp focus. No text, no labels, no borders, no watermark."
"Professional character reference sheet on a plain seamless white studio background, soft even lighting: three full-body views of the same boy arranged side by side from left to right — front view, three-quarter view, back view — with one large face close-up portrait at the far right. The boy is an eleven-year-old British schoolboy with very messy jet-black hair sticking up at the back, hazel eyes behind round wire glasses, a confident cheeky grin, wearing a rumpled navy knitted jumper over a white collared shirt and grey school trousers. Photorealistic, detailed skin and fabric texture, sharp focus. No text, no labels, no borders, no watermark."
Sirius Black — Three-View Promptgpt-image-2
"Professional character reference sheet on a plain seamless white studio background, soft even lighting: three full-body views of the same boy arranged side by side from left to right — front view, three-quarter view, back view — with one large face close-up portrait at the far right. The boy is an eleven-year-old British schoolboy with striking sharp aristocratic features, glossy shoulder-length black hair, pale skin, light grey eyes, a knowing half-smile, wearing a dark charcoal roll-neck jumper and black trousers. Photorealistic, detailed skin and fabric texture, sharp focus. No text, no labels, no borders, no watermark."
"Professional character reference sheet on a plain seamless white studio background, soft even lighting: three full-body views of the same boy arranged side by side from left to right — front view, three-quarter view, back view — with one large face close-up portrait at the far right. The boy is an eleven-year-old British schoolboy with striking sharp aristocratic features, glossy shoulder-length black hair, pale skin, light grey eyes, a knowing half-smile, wearing a dark charcoal roll-neck jumper and black trousers. Photorealistic, detailed skin and fabric texture, sharp focus. No text, no labels, no borders, no watermark."
Remus Lupin — Three-View Promptgpt-image-2
"Professional character reference sheet on a plain seamless white studio background, soft even lighting: three full-body views of the same boy arranged side by side from left to right — front view, three-quarter view, back view — with one large face close-up portrait at the far right. The boy is a thin pale eleven-year-old British schoolboy with light brown hair, tired gentle eyes, faint old scars across his face, a shy wary expression, wearing a patched oversized brown wool cardigan over a worn collared shirt. Photorealistic, detailed skin and fabric texture, sharp focus. No text, no labels, no borders, no watermark."
"Professional character reference sheet on a plain seamless white studio background, soft even lighting: three full-body views of the same boy arranged side by side from left to right — front view, three-quarter view, back view — with one large face close-up portrait at the far right. The boy is a thin pale eleven-year-old British schoolboy with light brown hair, tired gentle eyes, faint old scars across his face, a shy wary expression, wearing a patched oversized brown wool cardigan over a worn collared shirt. Photorealistic, detailed skin and fabric texture, sharp focus. No text, no labels, no borders, no watermark."
Peter Pettigrew — Three-View Promptgpt-image-2
"Professional character reference sheet on a plain seamless white studio background, soft even lighting: three full-body views of the same boy arranged side by side from left to right — front view, three-quarter view, back view — with one large face close-up portrait at the far right. The boy is a small plump-cheeked eleven-year-old British schoolboy with a round face, mousy brown hair, small round eyes, an eager nervous grin, wearing a slightly-too-small grey knitted jumper. Photorealistic, detailed skin and fabric texture, sharp focus. No text, no labels, no borders, no watermark."
"Professional character reference sheet on a plain seamless white studio background, soft even lighting: three full-body views of the same boy arranged side by side from left to right — front view, three-quarter view, back view — with one large face close-up portrait at the far right. The boy is a small plump-cheeked eleven-year-old British schoolboy with a round face, mousy brown hair, small round eyes, an eager nervous grin, wearing a slightly-too-small grey knitted jumper. Photorealistic, detailed skin and fabric texture, sharp focus. No text, no labels, no borders, no watermark."
Corridor Scene Promptgpt-image-2
"Cinematic photograph inside a 1970s British steam train: view down a narrow wood-panelled corridor toward an open compartment doorway, warm golden late-afternoon sunlight spilling from the compartment across worn emerald-green seats and the corridor floor; a brass luggage rack with a battered leather trunk; a grey owl blinking inside a brass cage hanging near the ceiling; steam trails streaking past the window. Soft film grain, warm nostalgic tones, photorealistic, no people, no text."
"Cinematic photograph inside a 1970s British steam train: view down a narrow wood-panelled corridor toward an open compartment doorway, warm golden late-afternoon sunlight spilling from the compartment across worn emerald-green seats and the corridor floor; a brass luggage rack with a battered leather trunk; a grey owl blinking inside a brass cage hanging near the ceiling; steam trails streaking past the window. Soft film grain, warm nostalgic tones, photorealistic, no people, no text."
Why Choose Neta Studio
Professional — a cloud harness runs the whole production from world building to roleplay direction to publishing, with no local setup. Stable access to the latest models: GPT Image 2 · BiRefNet · deepseek-v4-flash.
One-click generation — officially tuned skills drive every step: world building, roleplay drafting, character and scene art, transparent cut-outs, in-browser visual QA and one-click publishing, with world fork and resource sharing built in — so every portrait, scene and prompt in this story is reusable in your own world.
Community-first — users build unlimited worlds, and every public world can be forked, remixed and reimagined. Start from this train, or begin fresh from any idea — a one-line prompt is enough.
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Platform 9¾ was generated by Neta Studio AI from a single world prompt — the world took minutes, the roleplay and the artwork took minutes. You can do it too — step into this compartment or start fresh from any idea. No coding required, free to start.
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