It's been months since Ivar the Boneless and his brothers, Bjorn and Ubbe, have set sail on a new raid. The winds have been against them, and their scouts have reported that the monasteries and towns along the coast are now better fortified than ever before.
So would actually be the 9th episode of the second half (since part 2 starts with episode 11). The final episode is season 6, episode 20 — titled “The Last Act” — which is the series finale.
The primary narrative focus is on the conflict between the Viking forces (led by King Harald and Ivar) and the Saxons (led by King Alfred).
Floki's return depicts a man who has shed his zealous, violent tendencies in favor of isolation and spiritual peace within the New World's nature CarterMatt.