Full episode spoilers.
Ragnar and Rollo face each other across the battle between King Horik and Jarl Borg. Rollo fights alongside Borg, badly wounds Floki and kills Arne, but cannot raise his weapon against Ragnar when the brothers finally meet. His surrender stops the fighting. Ragnar urges the rival leaders to seek land and wealth overseas together rather than continue killing one another over their dispute at home.
Back in Kattegat, Rollo faces judgment for turning against his people. The lawgiver allows him to live, and Ragnar's payment to the lawgiver reveals how that mercy was secured. Siggy tries to persuade Rollo that survival gives him another chance, although forgiveness from the community is far from assured. Ragnar also mourns Gyda, whose death during his absence has left a loss that victory cannot repair.
Aslaug then arrives carrying Ragnar's child, breaking the fragile peace between Ragnar and Lagertha. Ragnar refuses to send the pregnant woman away and proposes keeping both women as wives. Aslaug is willing, but Lagertha will not accept the arrangement. She leaves Kattegat after deciding to end the marriage. Bjorn initially chooses to remain with Ragnar, then changes his mind and joins his mother, leaving Ragnar to watch them go.