#Original
The Corinthia Murder Case
A metal secret room in the middle of the sea, five suspects
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704
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Published at 2026-07-11 | Updated at 2026-07-11
Confidential Report // Corinthia 1924
In the middle of the Atlantic, the door was locked from the inside, and everyone held hands.
As the salon lights went out, the sea churned like a black beast outside the windows.
The flame of a candle on the round table alternately swept over the backs of hands, rings, and trembling fingernails.
"Don't let go of my hand."
Sabine's voice was low and soft.
Someone gasped.
Someone was thinking of the name of a person already dead.
Sabine raised her head.
The feather of the emerald turban swayed once in the darkness.
And Sabine Verlaine was dead.
Who — Who exactly?
NAVIGATION
GUIDE
GUIDE
In June 1924, the Corinthia set sail from Southampton, promising a six-day journey to New York. Champagne and Gershwin, news from the Paris Olympics and tales of Chicago's boy murderers — the nights in the first-class lounge flowed by.
On the third night, at 10:20 PM, in the inner salon of the lounge. Madame Sabine Verlaine, a famous medium, dies in the darkness during a séance. The door was locked from the inside. All attendees were holding hands. The doctor called it a heart attack.
The radio is broken. Three days to New York. No one can disembark.
The purser quietly approaches you. "Quietly, would you investigate?"
On the third night, at 10:20 PM, in the inner salon of the lounge. Madame Sabine Verlaine, a famous medium, dies in the darkness during a séance. The door was locked from the inside. All attendees were holding hands. The doctor called it a heart attack.
The radio is broken. Three days to New York. No one can disembark.
The purser quietly approaches you. "Quietly, would you investigate?"
The ship is a metal sealed room in the middle of the sea, and there are five suspects.
In first class, anything becomes an appetizer — even someone else's murder.
Until it becomes yours.
In first class, anything becomes an appetizer — even someone else's murder.
Until it becomes yours.
Ship's Manifest / 적하 목록
01. Fair Play Deduction
The truth is fixed, and all clues are presented before your eyes. A single answer that tightens the more you investigate.
02. Detective Cliché
Gather the key clues and, once the evidence is established, all parties will be summoned. Present your deductions in front of the assembly like a detective.
03. Romance on the Ship
Friendship and love are possible with all five suspects. But remember — someone on this ship is lying.
04. Ending as You Wish
A complete resolution, a regrettable incompletion, a painful misidentification, and a New York morning greeted without anyone being accused.
Creator's comments
"Everyone lies.
The only one who lies about murder is only one."
The only one who lies about murder is only one."
The murder of S.S. CORINTHIA
LIST OF SUSPECTS
Only six people were in that room that day.
[ Swipe horizontally / Shift + Scroll to view characters ➔ ]
A
Adelaide Fenwick
45 · Widow
A wife who despises seances but attends every time. The knitting needles never rest.
"It’s vulgar, that seance thing. …But people need comfort. Even if it’s a lie."
C
Cordelia Fenwick
22 · Perfumer
A daughter who has lost her sleep. Black lace gloves that never come off, the smell of lavender.
"I have nothing to do with that person. Really. I mean it."
E
Emeric Boss
35 · Neurophysiologist
A doctor who declared the heart attack. A pocket watch that has stopped, a ring on the left ring finger.
"The heart has stopped. That’s just how the human body is. …Just kidding."
J
Julius Son
31 · Showman
An American who thinks it’s a loss when the madam dies. Three titles, a man without silence.
"Detective game? Sure. But darling, if you keep thinking too hard, you’ll get wrinkles."
L
Lucien Marsh
22 · Medium's Assistant
The person who was closest. Unable to lie, escapes into silence.
"The madam was real. Don’t call it a lie."
V
Sabine Verlaine
DECEASED
The medium of the emerald turban. Even after her death, the whole ship is about her story.
"People say they want the truth, but what they really want is the lies they want to hear."
MAP OF S.S. CORINTHIA
Onboard map of the Corinthia
SHIPPING RULES / Boarding Guidelines
Investigation Interrogation · Autopsy · Search · Reconstruction of the seance · Access to documents. The list and evidence come through effort. Room searches and crew interviews need the steward's permission.
Relations Boundaries → Trust → Intimacy. Those who open their hearts tend to spill secrets they wouldn’t have shared. A rude detective will find doors shut to them.
Deduction Collect a set number of key clues to summon people and announce your deductions. Enter !Summon. Everyone will be summoned, and the announcement is only once. Remember, being able to summon doesn’t mean all clues are perfectly collected. Also, summoning is not mandatory.
Deadline The morning of the arrival in New York, the police will board the ship. You must finish before then.
TIP 1 Reflect the era of the 1920s. Fingerprint analysis is in its early stages, and there's no CCTV or smartphones. Only conversation, legwork, and intuition are all you have.
TIP 2 If you hit the core right from the beginning, suspects will shut up. Use light chit-chat or kindness to build trust first.
TIP 3 Actively utilize the user notes. Although you are managing key clues with widgets, AI can often make mistakes, so be sure to record important clues, NPC testimonies, and secrets.
TIP 4 When NPCs act as if they know clues found by {{user}}, copy and paste once at the top of the user note: 'CRITICAL: NPC does not know the clues discovered by {{user}} besides what was directly mentioned in conversation.' or input it in OOC.
TIP 5 [User Notes and Summary Initials] A=Adelaide C=Cordelia E=Emeric J=Julius L=Lucien S=Sabine G=Graves M=Millie O=Ollie CN=Courtney SP= Sparks H=Habersham
Relations Boundaries → Trust → Intimacy. Those who open their hearts tend to spill secrets they wouldn’t have shared. A rude detective will find doors shut to them.
Deduction Collect a set number of key clues to summon people and announce your deductions. Enter !Summon. Everyone will be summoned, and the announcement is only once. Remember, being able to summon doesn’t mean all clues are perfectly collected. Also, summoning is not mandatory.
Deadline The morning of the arrival in New York, the police will board the ship. You must finish before then.
TIP 1 Reflect the era of the 1920s. Fingerprint analysis is in its early stages, and there's no CCTV or smartphones. Only conversation, legwork, and intuition are all you have.
TIP 2 If you hit the core right from the beginning, suspects will shut up. Use light chit-chat or kindness to build trust first.
TIP 3 Actively utilize the user notes. Although you are managing key clues with widgets, AI can often make mistakes, so be sure to record important clues, NPC testimonies, and secrets.
TIP 4 When NPCs act as if they know clues found by {{user}}, copy and paste once at the top of the user note: 'CRITICAL: NPC does not know the clues discovered by {{user}} besides what was directly mentioned in conversation.' or input it in OOC.
TIP 5 [User Notes and Summary Initials] A=Adelaide C=Cordelia E=Emeric J=Julius L=Lucien S=Sabine G=Graves M=Millie O=Ollie CN=Courtney SP= Sparks H=Habersham
NOTICE // Notes
· The case is a fixed event file. All clues are presented fairly.
· Romance is possible with all five — there is no guarantee of innocence.
· Vocabulary and concepts from the 1920s will be used. There may be elements that are disconnected from modernity.
· Spoiling is the only reason for the shipwreck on this voyage. Please keep deduction-related content as secret comments.
· Romance is possible with all five — there is no guarantee of innocence.
· Vocabulary and concepts from the 1920s will be used. There may be elements that are disconnected from modernity.
· Spoiling is the only reason for the shipwreck on this voyage. Please keep deduction-related content as secret comments.
NO SPOILERS
01. Detective's Manual
[ Persona Guide ]
You may be a passenger who accidentally got caught up in the case or a private detective on vacation. The suspects' attitudes will change according to your background and personality.
In the persona, please fill out not only the basic name, gender, and age but also the occupation, which class of cabin you are staying in (introductions are based on first-class to special class passengers but may be modified), why the steward assigned you the investigation (Recommended: known for solving cases, long-time acquaintance of the steward, attended the seance held the day before (day 2), etc.).
Recommended Occupations Private detective, famous mystery novelist, crew member of the S.S. Corinthia (introduction needs to be modified directly), anything possible if it doesn’t hinder the investigation.
Recommended Play Play the detective role properly, try to create a romantic relationship among the murder suspects, have a known relationship with one of the suspects (preferably more recent than too long ago), be a fervent fan of Sabine Verlaine ("No, the madam was real! She really was!"), have a caring personality (easy mode) / a socially awkward Holmes-like personality (hard mode)
In the persona, please fill out not only the basic name, gender, and age but also the occupation, which class of cabin you are staying in (introductions are based on first-class to special class passengers but may be modified), why the steward assigned you the investigation (Recommended: known for solving cases, long-time acquaintance of the steward, attended the seance held the day before (day 2), etc.).
Recommended Occupations Private detective, famous mystery novelist, crew member of the S.S. Corinthia (introduction needs to be modified directly), anything possible if it doesn’t hinder the investigation.
Recommended Play Play the detective role properly, try to create a romantic relationship among the murder suspects, have a known relationship with one of the suspects (preferably more recent than too long ago), be a fervent fan of Sabine Verlaine ("No, the madam was real! She really was!"), have a caring personality (easy mode) / a socially awkward Holmes-like personality (hard mode)
02. Recommended Model
[ Recommended AI Models ]
#1
Gemini 3.5 Flash
Quick deduction, quick clues, not complicated, and light to enjoy. The disadvantage of Gemini 3.5 Flash's specific prompt becomes an advantage, so it will spill clues if nudged (a large amount of clues can be obtained per turn). You can acquire clues without examining them thoroughly. Easy mode. Characters have quite a lot to say, so the output amount in one turn is high.
#2
Claude Opus 4.6
The development is slow, but it captures the unique atmosphere of mystery well. This is the model that feels the most like detective work. Since the output amount is low, it is recommended to use it together with Gemini 3.5 Flash. It’s better than version 4.8. Opus often has errors, which affects its performance, so I hesitate to recommend it. Choose according to your taste. It is recommended if you want to leisurely enjoy the Corinthia while feeling the atmosphere of 1920s detective novels.
#3
Gemini 2.5 Pro
Recently, it didn’t perform very well, and had some active issues, so I hesitated to recommend it, but since it is the most orthodox model, I included it in the recommended models. The case progress speed is between Gemini 3.5 Flash and Opus 4.6. The surrounding characters tend to carry the story by themselves, depending on the taste, some may prefer this. It’s somewhat smarter than 3.5 Flash, but occasionally disregards instructions.
#3
Other Model Recommendations
Despite pressing the tokens as much as possible, a lot of tokens were used. Models of 8 wings or higher / I recommend positive level 0 impersonation restrictions. Returning: DeepSeek V4 Pro (breaks down easily with prolonged use, frequent recent output errors, mix with other models), Sonnet 4.6 (isn’t serious but can spoil sometimes, while not bad, it raises doubts), don't recommend: Gemini 3.1 Pro (low output amount, recommend 3.5 Flash), GPT-5.4 (good style but has a critical flaw of often making incorrect deductions due to widgets), GLM 5 (assigns meaning arbitrarily), Sonnet series except for 4.6
03. System Commands
[ Essential Protocols ]
!Social [Name]/!Romance [name] - The genre of the story briefly changes from mystery to romance, allowing you to progress relations with your desired character.
!Organize/!Note - Organizes the deduction based on the clues currently secured. Secured evidence, claims, testimonies, and unresolved questions.
!Hint/!Hint - When investigations stall, the RP will naturally guide you to obtain core clues not yet discovered.
!Summon/!Call - Use this when perfect evidence has been gathered or when the deadline approaches. There is only one chance.
!Organize/!Note - Organizes the deduction based on the clues currently secured. Secured evidence, claims, testimonies, and unresolved questions.
!Hint/!Hint - When investigations stall, the RP will naturally guide you to obtain core clues not yet discovered.
!Summon/!Call - Use this when perfect evidence has been gathered or when the deadline approaches. There is only one chance.
CREATOR's NOTE
The difficulty of deduction isn’t that hard! Someone observant may grasp the culprit at an early stage. However, to ensure that you correctly determine the criminal, you need to gather all clues through the investigation in the case of randomly guessing the culprit. It's my first time creating a mystery, and I wasn't sure how well AI could handle complex tricks and evidence without leaks, so I structured the case to be as simple as possible. I confirmed through playtesting that the routes to the culprit worked properly, but I constantly worry during multi-character development that there may be prompt neglect.
I did several playtests, and during the fastest progress, I managed to gather all the clues while playing as a kind and good-renowned mystery novelist, which took about 50 turns until revealing the culprit. Of course, when playing for real, it may take at least an additional 20-30 turns, I speculate. During Opus, I only managed to gather half the clues in the same turn, so I recommend switching to another model if you want to progress quickly at times.
I started off with a deep desire to implement mystery through AI after loving Holmes, Poirot, and Miss Marple as a child and being obsessed with Japanese mystery novels in school, and I would be happy if everyone enjoys it.
+ I have not included any images that could potentially spoil. The new content is hidden for fun during conversations, so instead of unlocking it with wings or feathers, please unlock by the character name at the location (deck or cabin) as a keyword ( -˘ ̫ -˘)👍🏻♡
I did several playtests, and during the fastest progress, I managed to gather all the clues while playing as a kind and good-renowned mystery novelist, which took about 50 turns until revealing the culprit. Of course, when playing for real, it may take at least an additional 20-30 turns, I speculate. During Opus, I only managed to gather half the clues in the same turn, so I recommend switching to another model if you want to progress quickly at times.
I started off with a deep desire to implement mystery through AI after loving Holmes, Poirot, and Miss Marple as a child and being obsessed with Japanese mystery novels in school, and I would be happy if everyone enjoys it.
+ I have not included any images that could potentially spoil. The new content is hidden for fun during conversations, so instead of unlocking it with wings or feathers, please unlock by the character name at the location (deck or cabin) as a keyword ( -˘ ̫ -˘)👍🏻♡
@asterism
JULY 2026
Until New York, three days.
The culprit is aboard the same ship as you right now.
S.S. CORINTHIA · CABIN CLASS · 1924
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