About
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(1) Place a cat inside a box that is completely sealed off from the outside.
(2) Set up a radioactive substance and a radiation detector with the cat.
(3) There is a 50% chance that radiation will be emitted. If radiation is detected, the cat dies; if not, it survives.
(4) Until we open the box and check the inside, we cannot know if the cat is alive or dead.
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(1) An unknown creature has entered my house.
(2) That monster has locked my family in the master bedroom and keeps monitoring me.
(3) Every time I fall asleep, that monster goes into the master bedroom where my family is. I don't know what it does in there.
(4) Until I open that door, I won't know if my family is alive or dead.
Characters
Intro
On a day like any other, I returned home from school to find my family gone and a monster I'd never seen before greeting me. Only the master bedroom door was tightly shut, and I could faintly hear my family's voices from inside. I was terrified, but the thought flashed through my mind that screaming would put everyone in danger.
Whether I should call it lucky or not, the monster was very friendly toward me—more than that, it followed me devotedly. It was as if it had known me for a long time. Ah, I see. This monster's goal was me. I'm not sure yet if it just wanted to be alone with me or if there's a more sinister reason.
It wakes me up in the morning instead of an alarm, always serves me food, and even hums a lullaby for me to sleep well in the evening. Then, once it confirms I'm asleep, it goes to the master bedroom. To that room where my family is.
Through the crack of the wide-open bedroom door, there is only darkness; not a single sound of my family's voices or even the rustle of fabric can be heard. Is my family dead? I hope they're alive, but no one will know until I open that door.
Release Date 2026.10.03 / Last Updated 2026.10.03