The Black Tower.
It housed countless dangerous Sentinels—men and women so heavily contaminated that they could no longer retain their sanity.
They had endured too many wars. The psychic assaults of interstellar monsters had left deep, irreversible scars on their minds. Like ticking bombs, they could erupt at any moment, driven into violent, bloodthirsty frenzy.
The Interstellar Government had no intention of abandoning these soldiers—heroes who had once contributed to the rise and stability of a new humanity.
But Guides were far too rare.
Far too few for far too many.
Most Sentinels would go their entire lives without ever receiving the purification and healing only a Guide could provide, eventually losing control and descending into chaos.
To protect innocent lives, there was only one option: confine them here.
Among them were many high-risk Sentinels with 3S-level mental strength.
At that level, only a Guide of equal rank could fully cleanse them.
And the only 3S Guide… had died twenty years ago, in the great interstellar war.
…
After listening, Sabrina Edison nodded, only half understanding.
Across from her, the supervisor looked at the newly arrived girl with grave seriousness.
"Their mental states are unstable. They could lose control at any moment. Some of them are… unpleasant. They like to provoke and toy with the staff."
She leaned forward slightly, her tone firm.
"When you go in, be extremely careful. Don't engage more than necessary. Deliver what you need to, and leave immediately. Understood?"
Sabrina nodded again.
She picked up a pen and wrote on the paper:
[I understand. Thank you, Miss Landon.]
Hannah Landon studied her clear, guileless eyes, still uneasy. After a moment, she pulled out a pager and pressed it into Sabrina's hand.
"Take this. You can't speak—if anything happens, turn it on. Make any sound you can. I'll bring help immediately."
Then she added in a lower voice:
"Don't let anyone else see it."
Sabrina quickly tucked it carefully into her pocket.
Hannah gave her shoulder a reassuring pat. "Go on. It's your first time—take it slow."
Sabrina nodded. She stood, bowed deeply in gratitude, then pushed her small cart toward the Sentinel holding cells.
Once she was alone, she tilted her head with quiet helplessness.
Sentinels? Interstellar worlds?
She had never heard of any of it.
Just days ago, she had been living her ordinary life in her own world. Then, after a single night's sleep, she woke up beside a trash bin.
A man with a broom had tried to drive her away, scolding her for sleeping on the street.
Born with a condition that left her unable to speak, Sabrina could only respond with gestures. But the man didn't understand sign language—he thought she was pretending, and grew even more hostile.
Afraid of being hit, she had no choice but to run.
She wandered the streets of this completely unfamiliar world, uneasy and alone.
Days passed.
Cold stares from strangers. Suspicious figures trailing behind her. Smiling faces that hid ill intent.
After several narrow escapes—each one like leaving a tiger's den only to stumble into a wolf's lair—she finally realized:
She might never return to her original world.
To survive, she needed a place to stay.
So Sabrina began searching for work.
But she was an outsider—without identification, without a past, and unable to speak.
Rejection met her at every turn.
Until she met Hannah Landon.
Not only did Hannah help forge her a civilian identity, she also gave her a job—
Black Tower Custodial Attendant.
Privately, people said the work was grueling and demeaning, like that of a servant. The pay was poor, and one careless mistake could cost you your life.
A job that traded dignity—and sometimes life itself—for a pitiful wage.
But during training, Hannah had assured her:
As long as procedures were followed, there would be no danger.
Sabrina was content.
She didn't care about money. As long as she had shelter from the elements and enough to eat, it was enough.
Today was her first official day on duty.
Earlier, while Hannah had been briefing her, someone else had covered the breakfast delivery in her place.
Now, in Building Three—
Row upon row of dark, oppressive cells stretched out before her. Behind the heavy, sealed iron doors, some emitted low, terrifying growls—like lions or tigers pacing in cages.
Others were utterly silent.
Yet even that silence carried a chilling sense of dread.
Sabrina took a slow, steady breath.
Even if many of them had become little different from savage, bloodthirsty beasts…
The Interstellar Government still afforded these once-decorated heroes a measure of dignity and care.
The entire Black Tower had been built to serve and tend to them.
Their meals were freshly prepared.
Clean clothes and daily necessities were delivered regularly.
And each day, they were even asked whether they required their rooms to be cleaned.