Fifteen years from now, a new virus sweeps the globe. 95% of those afflicted experience nothing worse than fever and headaches. 4% suffer acute meningitis, creating the largest medical crisis in history. And 1% find themselves 'locked in' - fully awake and aware, but unable to move or respond to stimulus. 1% doesn't seem like a lot. But in the US that's 1.7 million people 'locked in' ... including the President's wife and daughter. Spurred by grief and the sheer magnitude of the suffering, America undertakes a massive scientific initiative.
Nothing can fully restore the locked in. But then two new technologies emerge. One is a virtual-reality environment, 'The Agora', where the locked-in can interact with other humans, whether locked-in ornot.
The other is the discovery that a few rare individuals have brains that are receptive to being controlled by others, allowing those who are locked in to occasionally 'ride' these people and use their bodies as if they were their own. This skill is quickly regulated, licensed, bonded, and controlled.
Nothing can go wrong. Certainly nobody would be tempted to misuse it, for murder, for political power, or worse ...