Is Sansa's Invitation to King's Landing a Sign of Her Doom?

The following contains spoilers for Game of Thrones season seven.

Though there are A LOT of things happening in Game of Thrones' season seven episode "Beyond the Wall" and we are still in our feelings over it, there's one scene that piqued my curiosity. After having a very whispered conversation with Littlefinger about Arya finding the letter she wrote to her late brother Robb about their "treasonous father" from season one, Sansa receives a letter inviting her to King's Landing. It's never explained why she is wanted at this "gathering," especially since Jon will already be there, and leaving Winterfell without any real head of House would be ridiculous. Sansa sends Brienne to represent her interests, and after much discussion, Brienne leaves. I have to wonder, though, how legit is that letter? It comes at an awfully inconvenient time for the Lady of Winterfell, and it's a little suspect when you consider that it's sent from Cersei Lannister. There are a couple of reasons Sansa could have been sent that invitation back to King's Landing, and with Game of Thrones, any of them could be the winner.

This is the most logical of the options and also the least exciting. As Lady of Winterfell, Sansa is the head of a great House and it's expected that she would be invited to events like this. Especially considering that Jon, the King in the North (or not anymore?), is the one calling for the whole shindig. It's a little odd, since having two heads of a House in the same location is risky, especially when it's the South, and Starks never do well in the South, but we're going to assume there are no ill intentions with this explanation.

I know, I laughed while typing this up myself. But with Game of Thrones, you never know! Having learned that the late Lady Olenna was actually behind of the death of her son, Cersei has no real reason to hate Sansa anymore. Aside from her general disdain for the younger woman, she only wanted her dead when she thought she had a hand in his death. Now that she knows she was wrong, she could be wanting to make amends and use that to gain an ally in the North.

At this point, I wouldn't put anything past Petyr the Creeper. He has so many schemes going on in his head, it's hard to believe anything in the North doesn't have his dirty fingers in it somehow. It's totally believable that after convincing Sansa that she could use Brienne as a safety measure against Arya, he would create a reason for her to send her away (and thus inspire more fear from her). He knows there is absolutely no way Sansa would ever return to King's Landing, so she would have to send someone she trusts in her place, aka Brienne. That way, there's no one around who truly has the best interests of both Stark women in mind and who might be able to bring them back to neutral ground. Now he has Sansa paranoid about her sister and Arya seemingly out for her blood. All of his plans could be coming into fruition. Unless they're playing him . . .

My favorite theory of them all! While the letter inviting Sansa to King's Landing may be very real and well-intentioned, it also plays into the plans of the Stark sisters against Littlefinger. Both of them have shown to be quite intelligent and distrustful of Littlefinger, so most of the drama surrounding them these past few episodes seem ridiculous. Unless it's all a plan to get Littlefinger to believe he's succeeded in dividing the sisters and lure him into a false sense of security. When Littlefinger mentions Brienne and Sansa receives the summons, sending her away as her proxy is the perfect way to keep her out of his scheming, as well as prevent her from interfering with the sisters' agenda. I am placing all my hope into this theory because I really don't want a reason to dislike Arya anymore!

Whatever the reason, hopefully the season finale brings us some answers.