From the introduction:
Six years ago, we lived in an advanced society, an enlightened empire inhabited by dozens of species across hundreds of worlds. Direct neural interfaces (DNIs) were near universal; with just a thought we could communicate, control devices, or stream an experience directly into our minds. With a DNI you could control augmentations and the body you were born with was no longer a limitation. With a cyber arm, you could be as strong as an Olympian; with a cyber leg, you could outrun a cheetah. It seemed we had transcended all limits.
But six years ago, the dream became a nightmare. Something found us in the wireless.
We called it the Whisper. It was an indecipherable voice that reached out to us all, wormed its way into our minds through the wireless, and broke us.
Billions died.