Ari suspects the Romans of rebuilding their forces, so he seeks the help of an eastern tribal chief, Marbod. Ari’s brother, Flavus, arrives in Germania.

Germanicus accuses Flavus of being a traitor. Ari brings Gaius to the village and then seeks revenge against Marbod. Thusnelda is angry at Ari for lying.

Tiberius requires a test of Marbod's loyalty. Flavus proposes an offer to Germanicus. The tribal chiefs gather to name Marbod king but tragedy strikes.

Marbod confronts Tiberius and demands justice. Thusnelda and Folkwin set out on a mission. Gaius hides out in the forest and makes a shocking discovery.

The tribes prepare to attack the Roman camp before ships with reinforcements arrive. Segestes approaches Tiberius with a treacherous proposal.