The Captured (free version)

It begins near the end, with a man intent on destruction, who feels most of his humanity has gone. As with so many others. Set in a future where almost all sentient life on earth no longer exists. Yet something remains. People continue to live as if nothing has changed, unaware that they are no more than copied memories running in an artificial substrate.
In writing The Captured I've tried going some way to explore what defines sentience. And considered the following: Would a machine entity recognize the distinction between itself and biological life - if it could replicate thought and action? And if it could recreate the exact function of a living being what difference does it make whether as flesh or machine?
But also this is a human story, though sometimes viewed from an alien perspective...

Blurb: [Life is going well for Torbin. A successful career, a happy marriage. Then something strange happens ... and again. So he begins to wonder: has it all been a lie? There is someone who claims to have the answers, a man returned from the past - from the dead. Only it seems someone else wants the truth to remain hidden.

An alien visits Earth to study its people. Disguised as a human, her involvement goes far beyond mere observation. She becomes embroiled in a struggle to save what remains of humanity. But already a machine intelligence has transformed Earth into an unrecognisable world, and continues to spread ceaselessly across the galaxy. Yet there is one way to stop them, a weapon held by an old enemy that could itself wipe out all sentient life.

There are those who believe they can survive the ultimate destruction. But at what cost?]