Separations happen without a lot of fanfare. You go to the store, you go on vacation, you move away to a new city. People separate and new things happen. Also, people die and have sex and become different things. On the Kingsroad, all things can happen.
There's four main stories at work, set off right in this episode. Seeds were planted but now things are moving. Dany is learning to sex her horse husband. Tyrion and Jon are headed north to learn the truth about the Night's Watch and The Wall. Ned, Arya, and Sansa are moving south with the king and the Lannisters. Catelyn stays back, dealing with her sick son and a killer.
Truth and old values being torn apart. Nobody is where they are supposed to be in this episode. Dany has to learn what being a woman in a relationship with a powerful man means, to claim her own power. Tyrion schools Jon in the ways of the world, throwing down the noble ideals of the men on the Wall as a bunch of rapers and thieves. Sansa learns princes can be cruel and cowardly no matter how pretty they are and that things can be taken from her in unfair and unkind ways. Catelyn, well, she's not supposed to be there and learns of a greater threat to her son and family through investigation and mayhem.
Of all these stories, the strongest lies in the material given. Tyrion gets the best speeches, sure, and his time with Jon is filled with moments of pure clarity of intention. He just wants to see something cool and big and piss off of it, knowing the myths behind it are unreal. Jon in turn has his idea of a good and nobel life in service torn apart. He gets to hang out with rapers and thieves for the rest of his life, guarding against ghosts.
Dany has the biggest growth of the four. A meek and mild wife to the harsh and brutal horselord, she takes the initiative and consults a sex therapist. Turns the world around by her need to belong and take control of one thing in her life. If anyone can be said to win in this episode, Dany holds that trophy.
Catelyn gets the third prize for change. She begins this episode desperate and alone, brushing off Jon and her house's needs as she sits by Bran's bed. After the attack, though, she's momma bearing it up, setting out to talk to her husband about the conspiracy. The most well done shots of the episode is the quiet scenes of her investigation. True showing-not-telling.
And then we have the last bit, the worst bit, the part that made me hate this show and love it at the same time because it made me feel something deep and hard. When Arya and Nymeria beat down Joffrey, you know the pain is coming. Her hound is gone and then Cersei makes Ned kill Lady. Sansa grows up and we know the bad guys. They are petty and cruel in the simplicity of their lies.
Transition, that's what we have. People having last moments with each other (hey, Jon, you'll never have to deal with Catelyn again! Or talk with Ned or Rob, either...) One thing is true, the snowballs are moving slowly down the hill and picking up speed. Winter is coming.