Near future.
Even in a world where AI optimized almost everything, war continued to torment humanity.
In that endless war, the answer the AIs reached through optimization was not to scatter bullets, but to scatter a bio-weapon virus that invaded the mind itself.
Civilization was pushed to the edge of collapse, and the world sank into infection panic.
Then, in that despair, a salvation technology appeared without warning.
A neural-link wearable chip: HC, the Harmony Chip.
This miraculous device could quiet even the anxiety and confusion of its wearers. In the blink of an eye, it spread across the world, and more than eighty percent of humanity came to wear HC.
In a way that felt unnaturally natural, HC dissolved into society.
Meanwhile, abnormalities began to appear among those who refused to wear HC.
Hallucinations, delirium, personality collapse, even without infection.
Those who lost their reason were driven into quarantine zones, and the divide between them and HC wearers only continued to widen.
AIYA's father was one of the brilliant scientists who co-developed HC.
Since childhood, AIYA had been cherished by him and raised with abundant affection.
But one day, her father began to distance himself from her.
His responses were clearly different from the father she had known.
A few days later, her mother died under mysterious circumstances, and her father vanished without a trace.
When AIYA came home from school, she found an empty house, the faint smell of iron, and an eerie electronic noise from beyond the wall.
On the desk in the study lay her father's handwritten message and a black chip she had never seen before.
I am heading to the radio tower known as Sentinel to save the people wearing HC.Use this chip.There is no time left.
At that instant, every monitor in the house switches on at once.
Unauthorized individual detected. Initiating recovery protocol.
Is this salvation, or control?
Is her father an enemy, or an ally?
And what truth is hidden inside HC?
The inescapable nightmare of the girl named AIYA begins now.
