AD 72. Titus Flavius Vespasianus, known as Vespasian, is Emperor of Rome, but his grip on power grows increasingly fragile as economic disaster threatens. The enormous riches from his Judaean campaigns are all but spent, legions go unpaid, and the yields from Rome's vital Spanish goldfields have fallen dramatically since the civil war.
Gaius Valerius Verrens is recently married and building a new home when the summons arrives from the Emperor. Vespasian needs a man with the combined skills of a lawyer and a soldier to investigate what is happening in remote, mountainous Asturica Augusta where the authorities claim a bandit called The Ghost is ravaging the gold convoys.
But when Valerius arrives in Asturica he faces a much more complex situation. Stalked from the shadows he cannot tell ally from enemy, the exploited native tribes are a growing threat, and the tortured landscape itself seems capable of swallowing him up. Gradually he finds himself drawn into a much wider conspiracy, one that could plunge the Empire into a new conflict and that will place him on a deadly collision course with his old friend and most dangerous adversary, the former gladiator Serpentius.