In a pre-credit sequence, a massive Roman army arrives at the gates of a Dacian town. The Roman envoy asks them to open the gates, promising them life and liberty. The guard on watch asks who is making this demand, and gets the reply "the masters of the world". He responds "You will be when we will die". After the credits we see a Roman army commanded by General Fuscus (Georges Marchal) arrayed at the Danube waiting for the right moment to attack Dacia. Fuscus and Roman senator Attius plot to kill the decadent emperor Domitian, who has just arrived to take command. Attius's son Severus (Pierre Brice) is a subordinate commander under Fuscus. News arrives that the Marcomanni have risen in rebellion. Domitian decides to make a deal with the Dacians so he can use the army to suppress the rebellion. Attius is sent across the Danube with Severus and a small contingent of legionaries to negotiate. But as soon as he enters Dacian territory Attius is killed by a Dacian sentry. Severus returns to camp with his father's body, and Domitian orders an attack. In Dacia Cotyso (Alexander Herescu) and Meda (Marie-José Nat), children of King Decebalus (Amza Pellea), are hunting in the Carpathian Mountains. When news arrives that Attius has been killed Decebalus makes the mysterious remark that he was "the only Roman who was not supposed to die". Decebalus reveals that Attius was really a Dacian called Zoltes, sent to Rome 40 years ago as part of a plan to promote Dacian interests. He had been supplied liberally with gold annually so that he could become influential in Roman politics and keep Decebalus informed of events in the capital. When he died he had been carrying a letter to Decebalus informing him of Roman plans and dispositions.