Here’s what went down in episode 6, entitled “What Might Have Been” of season 4 of Vikings.
Lagertha (Katheryn Winnick) is performing a ritual over Kalf’s (Ben Robson) grave before she leaves to raid. She speaks to Torvi’s (Georgia Hirst) son and tells him to keep his friends close but his enemies closer and who should arrive, but Erlendur (Edvin Endre), the enemy personified. Taking her own advice, she invites Erlendur to travel to Paris on her boat.
Kattegat (Part 1)
Ragnar (Travis Fimmel) is also preparing to leave for Paris, but first he must initiate his eldest sons to Aslaug (Alyssa Sutherland) into the viking way. Reminiscent of when Bjorn (then played by Nathan O’Toole) also got his viking band, Aslaug is pissy, stating she thinks the boys are too young to go to Paris with Ragnar. Ragnar, on the other hand, reminds her of just how much danger they were placed in the last time he left them. So this is what a viking custody battle looks like. Then, later on when Aslaug is naked and breastfeeding Ivar, I can totally see how the boys could all end up as serial killers if left under the instruction of their mother, the very woman who thinks there is nothing wrong with her son bludgeoning another child to death for no good reason.