Into the Fog: The Vanished Valley Arc
Rain drums on the ruined glass roof as Aoi stands alone, hands jammed in muddy pockets. For five days, the world beyond his cramped classroom is gone. No city, no sun, only fog—so thick you can’t see your own hand. It’s been this way since the rapid sirens, and no voice crackled through the radio since then.
Miki laughs in dawn’s dull light. ‘It’s only water in the air, Aoi, it can’t hurt you.’ But she’s only trying to calm herself. Sota, the bruised track star, tests the truth and returns ill, his right shoe gone, feet cut up. Sachi, soft and quiet, has started seeing things peer in the haze; is she tired? Or is there something out there?
Each morning, one more supply vanishes. How would you keep going, not knowing what lies beyond the locked door? Aoi wants his little brother. Sota wants the next meal. Miki is still sure her phone will ring with her father’s voice again.
A landing is found in the library—flooded, dark, but filled with clues. Charts scattered with strange marks, all too clean in the dust, each jar of food marked in a new way each day. Sota: ‘You counting us already, Aoi?’ Shrugs. No one answers out loud, but fear is there in every cough.
The mystery deepens at night. Footsteps on glass. Drawers rattling where there’s no wind. A notebook turns up in Miki’s pile—a survival log, written in a calm, childish hand. It wasn’t here earlier. Who wrote it? They search and find it full of sketches of themselves, blank faces, clouds above where their heads should be.
Miki flips forward and laughs without real feeling, asking Sachi, ‘You drawn this to freak us out?’
Sachi says she hasn’t slept, shakes her head. Pages show two doors they don’t remember having seen. What kind of student draws these in rushes? One sketch looks fresh, the ink hasn’t dried yet.
Sota decides on a test. He ties string around his waist and swaggers out into the white outside the gym. Rope pulls sword sharp, then goes slack. Nobody can see past the haze’s edge even if they press cheek right to cracked glass. Is it only fog? Aoi looks away, whispering, Sandra… Did his brother just call his name?
Back safe, but Sota is changed. ‘It’s not wet. It’s empty. You don’t feel the air in there.’ Drops of sweat leave tracks on his cheek, but he’s not cold. Nobody can sleep that night. Why can’t they just walk out?
This arc digs further. Their school itself is strange now, logged with marks—each day, desk numbers drop by one. The survival log changes notes by itself. Water level drops from undisturbed sinks. Sachi is found high up on the roof at night, repeating, ‘There’s always someone watching.’ Have you ever felt that chill, even with friends close?
Flashbacks fracture the episode: what did each see just before sirens? Why can’t they put them together? Aoi stood by the art room door, but he can’t recall its color. Miki remembers sunlight, but she’s not sure what her ringtone was.
New danger arrives—the sound of typing from below. When Aoi and Miki creep down, there’s nobody there. But on a battered old laptop, where no power remained, a file opens: ‘Day 6. One leaves today.’ Inscribed in the log’s hand. 
Sota vanishes in the following dusk. Questions boil—did he leave by choice, or get pulled? The group fractures, all doors checked, all windows watched. Miki redoubles efforts to find a call out. Sachi won’t speak at all now. Aoi can’t help wonder—what if they really are alone?
The last page of the survival log now reads: ‘Day 7. The mist will lift when you look.’ Each stares, then laughs, but none feel less scared. Night strips their trust to bone. Aoi blames himself—had he missed a clue? Sachi starts drawing crosses on the wall.
The final scene—long shadows from lanterns wavering on blistered walls. A scraping sound. Someone, or something, is dragging something near the entrance. Will you dare to stay up and watch the doorway with them? Cliffhanger. Something’s just started moving in the mist again.
