One extra child born outside the whole
Humanity is fixed at exactly three billion people fused into a single networked organism, and each death is balanced by a scheduled rebirth, so every birth is a return. Then one child is born who fills no vacated slot and has no prior life, an unaccounted-for person in a system that assumed completeness. The novel follows how the collective responds to this surplus individual, testing whether a closed, self-replacing humanity can absorb or even recognize a genuinely new person.
