The basic outline is that the world is reassembled from pieces from across history. Into the fray are plunged three UN helicopter crew from 2037 patrolling the south west Afghanistan region, a fort full of British and Indian soldiers from the 19th Century at a point in the infamous NW frontier (next to Afghansitan, by coincidence and including no less than Rudyard Kipling), the crew of a Soyuz capsule orbiting over central Asia (by luck!), 13th Century Genghis Khan, the ancient army of Alexander the Great and a “missing link” type ape woman and her child. These are central the story line. Most other humans in that crop up along the way, don’t last long.
Our main characters find themselves suddenly in a disrupted world, surrounded by different time zones. Most have no idea, initially, that anything has happened, although most are bewildered by the sudden apparent movement of the sun in the sky. And then there are the mysterious silver spheres floating silently and immovably at various points across the land.
This reconstruction of Earth in effect makes the world a hotch potch of time where everything and everybody left is in an isolated pocket of their own time. The Earth itself is terribly disturbed with pockets of ice age glaciers in amongst temperate zones, volcanic activity etc. all trying to find a new equilibrium.
What time slip fans always like is how people cope in unexpected circumstances, how they can use their knowledge (often historical) to overcome the crises they face and in the case of military stories, how a few men with modern weapons can defeat overwhelming hordes of historical foes! There is plenty of this sort of thing going on to keep us all amused but with the bonus of well written characters and detailed historical references.

What didn’t sit comfortably was the choice of characters thrown together. UN helicopter crew crashing near to a British NW frontier fort OK, but did it have to include Kipling?. Soyuz crashes to Earth and are picked up by Mongol nomads fine, but did it have to be Genghis Khan? The British encounter a large ancient army, but did it have to be Alexander’s army? There were simply too many celebrities. It may have been the intention of the mysterious force that created the patch work Earth to deliberately throw these different elements together, but this is never revealed or in any other way justified. It seemed the time discontinuity was just a lame excuse to thrust Macedonians against Mongols with a few other characters as dressing.
In addition, too many characters seemed to easily accept the theory of their new position in time, that everyone they new and loved were gone. No one seemed overly disturbed by this or make any serious quest to return home.

Having said that, the story was well crafted and quite compelling reading with some epic moments.