[Warning: spoilers for Season 4, Episode 4 ahead]
Well, well, well. It seems like everyone is in a good spot right now — oh, wait — everyone, but Ragnar apparently.
Things in Kattegat are uneventful in 'Yol,' so much so that Ragnar finds time to get to know Yidu, the slave he's been keeping a keen eye on of late. They stare, and they talk, and they stare some more. Then he takes her to his special place (no pun intended) and tells her she's free to "come and go as she pleases" (there's a lot of that going around the show). Queen Aslaug, of course, realizes what's brewing and tells him to go for it (like he did with her while he was still with Lagertha, I suppose), and so he does.
These two don't seem to be getting along much and everything serves as a reason to sharpen their claws. This episode it happened over little Ivor and lately, in the silent exchange of hate by the bonfire. It seems no surprise then that, when a new arrival comes to Kattegat, proclaiming himself "king of all Norway," Aslaug charms her way into his grace. Although, it's fair to say they've known each other prior and were even promised to each other — based on their innuendo. Likely, this 'king' has come to collect his bride after all. Enter Ragnar and Bjorn, now back from his trip to manhood, and the episode closes with its best line, delivered by Ragnar to the stranger: "And you are?" [fades to black.]
Back in Paris, Rollo and Gisla have (frigging finally) begun getting along, I mean really getting along, so to speak. He's learned enough of the language to stun the Pope's representative sent to annul their wedding, and even Gisla was impressed by his skills (all of them, apparently). They not only remain in matrimony, but they actually consummate it — a couple of times.
Bjorn eventually decides it's time to go back home and on his way to Kattegat, meets the assassin sent by Earl Kalf and Erlendur to kill him. He manages to kill the berserker after getting cut on the face (another scar to show off), and retrieves Erlendur's ring from the body. He then takes it to Hedeby, where he meets his mother and faces both the Earl and Erlendur, and just when you think he's going to kill them, he decides he just wants Erlendur's wife (wait, what?). And just like that, she goes with him to Kattegat — leaving her son in Lagertha's care.
There are two honorable moments still worth mentioning: One is the party theme that went on this episode, with Ragnar/Yidu sharing their psychotropics, Aethelwulf/Kwenthrith flirting openly, and the festivities in Kattegat that left Floki in the cold. Another is the arrival of king Aelle of Northumbria, who is bound to get things rolling faster than anyone else (and who's declared he's pledged to kill Ragnar). It seems we'll get to see all sorts of fighting in the next episodes, from glaring, to verbal offenses, culminating (I hope) in some epic battle between Ragnar and whomever gets in the way of the throne.