Summer, 30 BCE, Octavian Caesar's legions have entered Alexandria, Marcus Antonius and Cleopatra Ptolemy are dead by their own hands, bringing to an end, decades of bloody civil wars and a power struggle for the control of the Senate, Rome and her expanding empire. Now only one man remains, the adopted son of Gaeus Julius Caesar, Octavian. Exalted general and shrewd politician, now stands as the most powerful man upon the earth. Pulled by a destiny written before he was born, he knows for Rome to thrive, he must rule through peace - the Peace of Rome, and the way to maintain the Pax Romanum is to make war elsewhere, and he begins with the barbarian lands beyond the Haemus Mountains, inhabited by powerful Celtic tribes. He knows, as every Roman knows, the greatest danger to the security of Italy and Rome lie beyond the insecure boarders of her European provinces. The only way to secure Rome against this centuries old lingering threat, is to conquer them up to the mighty rivers of the Danubius, near two thousand miles long, and the Rhenus, which offer perfect natural boundaries to mark where civilised Rome ends and the savage barbarian begins. The rivers also offer great tactical advantages, not least the navigable inland access to the Euxine Sea and the Oceanus Germanicus practically the entire year round, giving Rome supreme tactical and commercial advantages. Mamertinius is quite extraordinary for his age, but he has had to grow up fast, living most of his life on the road with Caesar's master spy and assassin. Mamertinius is the son of the infamous and villainous First Centurion of the Fifth Macedonica, Nepos Maximo, the Bastard of the Aventine, but was raised by the equestrian, Draco Cerialis, who has invested all his knowledge and skills, raising him as his own son and teaching him the old ways of the warrior. Draco is murdered by Antonians in Egypt, Mamertinius has managed to escape with his life, killing two of Draco's assassins and carrying Draco's report for Caesar, he has managed to sneak through enemy lines to join up with General Calvinus' legions during the last stages of Caesar's pincer on Alexandria. With the preparations of the invasion of Moesia under way, Calvinus sends the young Mamertinius to be reunited with his estranged father in Macedonia, where he is to join the Fifth Macedonica as a part of his cover before embarking on an important mission into Moesia. While political machinations are abound in Rome, in Macedonia, Mamertinius departs on his mission into Moesia, where he is to deliver gold to seal Rome's alliance with King Rholes of the Scythian Getae, and return with a number of Scythian hostages and tribal leaders back to Macedonia. But there is malcontent among some of the Scythians, their ringleader, Prince Budorix who is determined to scupper the alliance and unite the Celtic tribes of Moesia against the Romans in the coming war. Budorix manages to murder several Scythian tribal leaders and some of the Romans (including Mamertinius' friend Deretinius). Budorix escapes to rally a Celt army to stop the Romans before they reach the city of Ratiaria on the Danube River... During this same period, the Roman conquest begins. Mamertinius and the remaining Scythians and Romans in escort manage to get back safely to the Fifth, his mission accomplished, Mamertinius is expected to return to Calvinus in Rome, but Mamertinius refuses to return, insisting he remains a soldier for the duration of the war, to seek vengeance against Prince Budorix, who he has vowed to the gods to kill...