San Francisco, 2017. In an alternate time track, Hillary Clinton won the election and Donald Trump's political ambitions were thwarted. London, 22nd century. Decades of cataclysmic events have killed 80 per cent of humanity.

A shadowy start-up hires a young woman named Verity to test a new product: a 'cross-platform personal avatar' that was developed by the military as a form of artificial intelligence. And characters in this future are using technological time travel to interfere with elections unfolding in the distant past . . .