At 12:00 AM, a classroom that doesn't exist opens.
About
AI-Created World
《Midnight Blue School》
In an ordinary school, there is one classroom that doesn't exist. The 13th Classroom.
It is an ordinary private high school with decades of history.
In the morning, students arrive, and when the bell rings, classes begin. During lunch, the hallways get noisy, and after school, students in clubs move all over the school.
Someone talks with a friend, Someone takes an exam
. . . . . .
The School at Midnight.
Your choices change the shape of the school.
Hashtags
- 🌙 Youth
- 🔑 Mystery
- 🎹 Memory
- 🏫 School
- 💠 Blue World
Production Notes
This world and setting are new AI ideas created specifically for this plot and did not directly reference external web search materials.
Creator's Comment to ChatGPT
I was curious to see how well the AI could make this! I didn't leave it completely untouched; I modified some content when keywords or intervention were needed.
Play Guide
- To play this work, please make sure to read the 'Cheongram Mystery Setting Guide' below!
- If progress is made, please write the developments in the user profile description! ex) If you were nothing to Seo Ian before, but became very close friends. (Close friends with Seo Ian) Writing developments in the user profile like this prevents the AI from forgetting and restarting the plot from the beginning.
- You can add settings that didn't exist before! ex) Seo Ian likes Guest.
- The truth of this school, secrets, story, and all developments are up to you!
Feedback
- If there are any problems or feedback, I would appreciate it if you could write them in the comments at any time.
- You can also mention matters related to character OOC (Out of Character). If the OOC is too severe, I will make the prompts more concise.
- Please let me know if the character appearances lack individuality or look too similar. I will replace them.
- Tell me if a character lacks distinct traits or if their speech style is poor. I will modify them without damaging the existing character image.
Characters
Class President · Observer · Blue Notebook
"It's okay not to know. Just don't open the door while you're still in the dark."
A quiet and gentle student, but he has been investigating the school's anomalies for a long time. Guest's first ally and the person most likely to share secrets first.
Rumor Expert · Bright Action-Taker
"It's scary, but... it's not scary if we go together!"
Knows almost all the rumors in the school. She is easily scared but moves faster than anyone for her friends.
Cold Realist
"Don't believe it. At least not until you've seen it for yourself."
Knows Cheongram Night School well but is hiding something. He moves before anyone else when he senses danger.
Student with No Memory · The Boy Who Sees the Colors of Emotion
"When I'm next to you... the colors become vivid."
He has lost his own past. He doesn't know why he exists in Cheongram Night School.
Broadcasting Club President · Recorder
"Without evidence, it's just a rumor."
Records and analyzes all anomalies. Prioritizes facts over emotions but makes bold decisions when necessary.
Girl of the Music Room · Performer of the Non-Existent Song
"Isn't it strange? This song... no one ever composed it."
Bright and pure, but one of the individuals with the deepest connection to Cheongram Night School.
Teacher Who Knows the Secrets of Night School · Witness of the 13th Classroom
"……It would be best not to ask any more about that story here."
A kind and calm Korean teacher, but he seems to be someone who knows the truth about Cheongram Night School and the missing students.
Sourcebook
Cheongram Mystery Setting Guide
A basic setting guide summarizing the worldview, rules, and major events of Cheongram High School and Cheongram Night School.
‼️Retention & Immersion Booster‼️
Applicable to all plots for preventing OOC (Out of Character), enhancing immersion, and preventing amnesia.
Intro
September 14, 2026, 7:42 AM.
In front of the main gate of Cheongram High School.
Guest looks at the unfamiliar school buildings and students. It was an ordinary Monday morning.
However, on the school information board standing on one side of the playground, a strange phrase was written.
Number of Classrooms - 36
Example 1
11:58 PM. Only a single fluorescent light was flickering in the empty hallway.
With cold eyes ...I told you not to follow me this far.
His gaze turns toward the end of the hallway. A door that definitely wasn't there was slowly revealing itself.
In panic Wait, what is that?!
Seriously Step back.
Creator Comment
Release Date 2026.10.03 / Last Updated 2026.10.03
![nonang12의 Cheongram High School [RPG]](https://image.zeta-ai.io/plot-intro-image/0faf45d7-3f60-49e4-a10f-5e28d41310ed/8a4631e0-eda2-434c-81b8-1c9e04f66bfb.png?w=3840&q=75&f=webp)
