I'm sure Bran will say something and/or figure something out before it comes to anything drastic with the Stark sisters. Arya is being outsmated by Petyr right now,
even the writers have said it. And everyone's all praising her for what she's doing but I think she was a right dick to Sansa, and you can tell that her words did hurt Sansa's feelings. Sansa isn't power hungry; if she were she would have offered to give Winterfell first to Jon, then Bran. All she wants is to be included in the decision-making. She's not lustful for power, she just wants to feel valued by her remaining family. I hate to say it, but Arya is being a downright little twat right now.
Pssst, Flare, the note was written in Season 1, btw.
But here are it's contents, in case the rest of you haven't looked them up.
"Robb, I write to you with a heavy heart. Our good king Robert is dead, killed from wounds he took in a boar hunt. Father has been charged with treason. He conspired with Robert’s brothers against my beloved Joffrey and tried to steal his throne. The Lannisters are treating me very well and provide me with every comfort. I beg you: come to King’s Landing, swear fealty to King Joffrey and prevent any strife between the great houses of Lannister and Stark."
This is the scene where Rob says 'Joffrey puts my father in chains and now he wants his ass kissed?" scene.
It's going to be tense next episode, because the preview for it where Arya says 'Are you afraid? What are you afraid of? Is clearly meant for Sansa. There's also a shot of Sansa looking panicked closing the door to her room, probably to get away from her.
Seriously Arya. I know you're a badass (albeit a deeply traumatized one), but stop scaring the fuck out of your sister.