Kevin Stiles was told he would go through two months of intense astronaut training and then have his memories uploaded into a computer. After that, he would go home to his family and continue with his life. And long ago and impossibly far away, he assumes he did that. But this version of Kevin finds himself on a ship in deep space, a clone of himself with all his old memories, on a mission to propagate the human species. His old life no longer exists. In all likelihood, Earth no longer exists. Kevin must forge a life for himself and his female companion on a world where humans are the aliens.
My favorite genre is probably "portal" science fiction where someone from today or near future is whisked away to a distant world or future. Here, we have both as a humanity-saving mission spanning billions of years goes awry. It's a familiar concept, but with several new, thought-provoking twists. Good read.