After the prophecy about Rollo's leadership comes true, the conflict escalates between the Vikings. Ivar leads a rebel army to kill Lagertha and her son for causing his mother's death.
In the wake of Ragnar Lothbrok's death, his sons split up after they avenge him. Two of them sail to the Mediterranean Sea as the rest stay behind to jointly rule their land in East Anglia. But trouble is on the horizon as the brothers are pitted against each other.