: As Rollo helps the Franks design advanced defenses—including massive river chains—Ragnar prepares for a second raid on Paris, setting the stage for an inevitable and tragic brother-vs-brother showdown. Shifting Alliances and New Faces Vikings season 4 episode 1 review: A Good Treason

: Rollo fully embraces his new life, going so far as to slaughter the remaining Viking camp outside Paris to secure his position with Emperor Charles.

Ragnar returns to Kattegat wounded and physically broken. While he lingers in a fever dream—seeing the gates of Valhalla slam shut in his face—a power vacuum forms.

While Ragnar recovers, his brother remains in Paris, having been granted a dukedom and the hand of Princess Gisla .

The first part of (often referred to as 4A) is a gritty saga of fractured loyalty and the heavy cost of power. Picking up after the brutal siege of Paris, it follows Ragnar Lothbrok's decline as he struggles with illness, betrayal, and a waning sense of purpose. The Return to Kattegat