In the year BC 35, it is recorded that 145 Roman soldiers settled in northwestern China. How did they get there? This novel creates a narrative starting thirty years before, following the fortunes and misfortunes of one of those soldiers, Marcus, as he fights with Julius Caesar in Gaul and with Marcus Licinius Crassus against the Parthians. Some of the Roman soldiers are taken prisoner by the Parthians but escape and head eastwards. This story from more than 2,000 years ago spans continents and the ages and provides a base for one of the most fascinating mysteries of northwest China.