The plot thickens.

Chaos is a ladder and this article has spoilers. You know what's coming next. After years of deception, lies and treachery, you can't help but get the feeling that Littlefinger's time in Game of Thrones is almost up. This being said, Petyr Baelish has mastered the art of staying one step ahead of his enemies, but with Bran's all-seeing powers and Arya's expert stealth,  he's fighting a battle that surely he can't win? The catspaw dagger could ultimately prove to be his undoing, but Game of Thrones fans were far more interested in the raven scroll that he demanded from Maester Wolkan near the end of the episode. As we've seen in an earlier episodes, Maester Luwin kept a record of every raven scroll that was sent to Winterfell. Here's a screenshot of what Arya saw when she retrieved that scroll from Littlefinger's mattress. The signature at the bottom is from “your faithful sister Sansa,” and in the letter, we can see references to King Robert’s death, an individual that's trying to “steal his crown,” and an urge for somebody to swear loyalty to King Joffrey. The text in full reads: "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. Your faithful sister, Sansa" This sounds like the exact contents of a conversation that Sansa had in King's Landing after she believed Ned Stark was trying to steal Joffrey's crown. As you can see in the clip below, Cersei, Grand Maester Pycelle, Varys and Littlefinger were all present in the room. After the Lannisters conspire to have Ned Stark declared a traitor, Littlefinger says that "a girl is innocent your grace, she should be given a chance to prove her loyalty."  Moments later, Cersei implores Sansa to send a raven to Lady Catelyn and Robb Stark in a bid to get Robb to swear fealty to Joffrey. Being a child and naive, Sansa was coerced into picking up the pen and writing to Winterfell. https://www.youtube.com/watch?v=-Bkb6tedTRs Clip via -  Sniper Mage When Sansa's letter arrived, Robb Stark and Maester Luwin saw right through it. They knew that Cersei had put those words into Sansa's mouth. Rather than swear loyalty to Joffrey, Robb decided to call his their bannermen and urge them to stand alongside with House Stark in rebellion against the Lannisters. https://www.youtube.com/watch?v=p9jjjMqtGpw Clip via - Miguel Ress This being said, at the present moment, Arya has no idea that Sansa's note was ever sent to Winterfell and given the fact that there's very clear tension between the Stark sisters, this is something that Littlefinger might be looking to exploit. That's probably the reason why he was seen smiling when he saw Arya leaving his bedroom. Arya's young, fiery and unwilling to compromise - exactly the type of person that Littlefinger can manipulate. As we've already seen, Sansa and Arya have completely different ways of dishing out justice and dealing with people. In this chaos and uncertainty, Littlefinger thrives. As D.B Weiss said in the latest Inside the Episode segment, "Arya is very used to being cleverer, stealthier and smarter than the people she's up against but she hasn't dealt with Littlefinger in a while. She gets roped into spying on someone who's actually leading her onto something that he wants her to have. He's looking for a way to prevent this sister bond from developing further because the tighter that bond is, the more definitively he's caught on the outside of it. On the Sansa end of the relationship, he sees the opening, but for Arya, all he has to do know is give her cause to display real rage towards Sansa. He knows full well with what's going on in Sansa's head regarding Arya and how dangerous she is. When Arya starts to act dangerously and angry, he knows where Sansa is going to turn." You can see the full discussion below. Littlefinger is playing a very dangerous game, but can he successfully drive a wedge between the Stark sisters? We shall see. https://www.youtube.com/watch?v=aNDV1EEvGHc&t=68s