The battle for supremacy begins as the ancient world splits into two: Roman vs. Barbarian. Hannibal of Carthage builds the first great alliance to defeat Rome before it becomes an unstoppable machine. The general launched a bold and unprecedented campaign to strike at the heart of the Republic: he conquered the Alps and entered Italy in the direction of the capital, leaving a trail of destruction in his wake. But, although Hannibal wins the battles, at the same time he is losing the war. Rome, with no adversary to stop its advance, traverses barbarian territory by plundering it and executing bloody revenge against the tribes who were fighting alongside Hannibal. Thus emerges the first wave of resistance in a 700-year fight for freedom. In Hispania, Rome seeks revenge on the barbarians who fought alongside Hannibal in his failed campaign to end the Republic. Governor Galba almost annihilated the Lusitanians, a Celtic tribe from the west of the Iberian Peninsula. The survivors, who live as refugees in their own land, unite around the former pastor and leader Viriato and organize a resistance guerrilla against the Roman occupation. The barbarians take advantage of their knowledge of the terrain to continue the fight, while Vetilio launches a large-scale operation with the aim of hunting down the elusive rebel leader. The two sides meet in the Tribola forest for a fatal clash.

Rome, which already dominates the Mediterranean with an iron hand, sets out to conquer new lands and takes the barbarians who inhabit them as slaves. But, the more it grows, the more enemies it gains within its borders: a vast barbarian army waits, in a dormant state, for its leader to emerge. Spartacus, a barbarian slave forced to fight as a gladiator, becomes the tenacious commander of an uprising that poses the greatest threat to Rome in a century. The Republic becomes an empire and continues its policy of romanization aimed at civilizing the barbarians. However, not even the first emperor, Caesar Augustus, is aware of the rebellion that is hatching within his own ranks. Arminius, the son of a German barbarian chief, is sent as a hostage to Rome as a boy and later becomes one of the highest ranking barbarian officers in the Imperial Army. But, when he is sent to his homeland to put down an uprising, he has to make the decision of who to be loyal to. The Battle of the Teutoburg Forest places the Empire on the brink of the precipice

Barbaric resistance becomes a life and death fight against the Empire. The Germanic tribes are united for the first time around a single leader, Arminius, who organizes a masterful ambush to expel Rome from his native land. The Empire needs expansion to survive, and it targets the barbarian fortress of Britain, where the Celts fight the invasion with unprecedented ferocity. Boudica becomes leader of the Iceni, and when she and her daughters are brutally humiliated by the Empire, she vows to take merciless revenge with the help of various Celtic clans on the island. Boudica tries to crush Rome with his own wild game in one of the bloodiest rebellions in history. Centuries of costly barbarian wars have their consequences on the Empire and end the era of expansion. Meanwhile, a dark threat emerging from the east plunges the Roman border into chaos. The Goths seek refuge in the arms of their enemy, Rome, but find only treason. Wrong decisions by the Empire trigger the catastrophe in Adrianople.

The Roman Empire is the world's first superpower, but it has grown so large that its size is more of a weakness than an advantage. Furthermore, the high cost of keeping barbarians under control, both in gold and in human resources, weakens the once powerful Army. Rome is divided into two empires with two emperors: that of the East and that of the West, and when the leaders of both sides attack each other, the Goths are again caught in the crossfire. Alaric leads his own to the gates of Rome and delivers the first in a series of deadly blows to imperial power. The Huns emerge in the east and bring chaos to the world: Attila seizes power and begins a reign of bewilderment and destruction, as wave after wave of barbaric avengers attack a Roman Empire fighting on too many fronts. In the midst of confusion, the last great barbarian leader, Generic "cunning and calculating king of the vandals" becomes the architect of the destruction of Rome.