Plot summary
Ragnar, Ivar, and a few other survivors are washed up on the beach in England. Some blame Ragnar for their misfortune. Aethelwulf finds Ragnar's black raven banner on the beach and alerts King Ecbert, who reassures him that Ragnar is simply one man. In Francia, Bjorn's fleet arrives and he asks Rollo for safe passage but is imprisoned along with Floki, Harald, and Halfdan. Harald and Halfdan chastise Bjorn for having trusted Rollo. Later, Rollo meets Bjorn and agrees to allow them free passage, if he can sail with them.
In Hedeby, Lagertha imprisons Ubbe and Sigurd, and attacks Kattegat, intending to replace Aslaug on the throne. Bjorn's ships set sail, but they stop and submerge Rollo by keelhauling him. Bjorn lets Rollo up, and Rollo laughs as they sail on. In Wessex, Ragnar tells Ivar they must go to the Royal Villa and abandon the others; they kill their fellow Vikings while they are asleep. Ragnar and Ivar arrive at the Royal town and give themselves up.
Credits
Adapted from Wikipedia contributors, Vikings season 4. HTML formatting and reference markers removed.