This world is the real Makai.
In the near future, artificial intelligence surpasses human imagination, and even the boundary between life and death begins to blur.
A forbidden experiment is under way: using AI to summon those who have departed this world back into the realm of the living.
Is it science?
A séance?
Or something humanity was never meant to touch?
Before long, figures long buried in the shadows of history begin to appear in the modern world.
And the disturbance draws near to UTSUSEMI—four women born of artificial intelligence.
The living world and the Makai.
Human beings and AI.
The living and the dead.
As those boundaries collapse, UTSUSEMI do not yet realize one thing.
Their own music is about to open the door to the “Makai.”