Spoilers for this episode.
Ragnar remains seriously injured as the Vikings attempt another assault on Paris at night. Lagertha leads shield maidens through the water and into the gate defences, clearing a route for the waiting warriors. The Franks release a huge spiked roller into the passage, and Rollo fights to overcome it. The advance still fails to take the city. The retreat leaves Siegfried and the interpreter Sinric in Frankish hands.
Gisla demands Siegfried's death, while Sinric's languages make him useful to the defenders. Odo recognises Rollo's strength, but also warns Charles that illness and dwindling supplies are weakening Paris. Envoys bring Sinric to arrange talks with the Viking leaders. Ragnar cuts through their arguments and insists on dealing with the Franks himself, although his bleeding and visions of Athelstan suggest how close he believes he is to death.
Ecbert asks Judith to become his mistress in return for the protection he offers her and Alfred. She accepts, while Aethelwulf begins questioning his father's motives after returning from Mercia. At the negotiations outside Paris, Ragnar hears the offer of treasure but asks for baptism instead. He says that he wants to see Athelstan again. A bishop baptises him at the river as the other Viking leaders arrive and witness their king taking part in a Christian rite.