Ragnar's reappearance in Kattegat triggers a chain of events no one - except the Seer - could have ever imagined. He unexpectedly arrives home to see what has become of his sons and to handle unfinished business in Wessex with King Ecbert. Meanwhile, Lagertha plans a power play in Kattegat and Bjorn prepares to fulfill his long-held dream to explore the Mediterranean in a sleek new boat built for him by Floki.