A man called Clay is swept into a far-future on an Earth which knows nothing of Shakespeare, Mozart, Mohammad or Darwin. It is a planet inhabited by beings of great intelligence, ambivalent sexuality and extraordinary powers. Slowly, Clay, as he embarks upon a panoramic journey, encompassing a billion years, understands that the twentieth century was no more than a minute fibre in the band of time and was no more than the dawn of man. What has followed is the time of the Son of Man.