Az évadnyitó epizód időszámítás után 43-ban játszódik, kilenc évtizeddel azután, hogy Cézárnak nem sikerült meghódítania Britanniát. A rómaiak most visszatérnek a szigetre, hogy uralmuk alá hajtsák. Claudius császár Pannónia egykori helytartóját, Aulus Plautiust bízza meg, hogy négy légióval foglalja el a szigetet. Úgy tűnik, könnyű dolga lesz az eltökélt parancsnoknak, vele szemben ugyanis egymással viszálykodó kelta törzsek állnak, amelyek háborúban állnak a druidával és az isteneivel is.

Having marked Rome's arrival with blood, Aulus sends envoys to parlay with the tribes of Britannia, while also looking to learn more about the Druids.

Aulus is reborn, but his destiny remains unclear. Cait is able to locate her father, but she can't free him from the Roman camp alone.

King Pellanor disowns Kerra and leaves her life in the hands of the Druids. But the gods' judgement is not what he expected.

The gods have spoken, but Kerra must decide if she will accept their ruling. Antedia seals an alliance with Rome - on one condition.

After their long ordeal, Cait and her father finally arrive at the safety of the Cantii citadel, but a demon is on her trail.

Cait and her father seek shelter in the ruins of their old home, where she is visited by someone she never expected to see again.

The battle of wills between Kerra and Antedia intensifies, as the Regni play their trump card. Aulus enlists deadly exiles to find Cait.

The end appears to be close for the Cantii, and Aulus unveils how the Roman Empire truly conducts business.