The following contains spoilers for Game of Thrones season seven.
I'll be the first to admit that the Winterfell plot line during Game of Thrones season seven has left something to be desired. Hell, I even used the absurd tension between Arya and Sansa Stark as backup when I declared Arya the most overrated character on the series. But I'm always willing to change my mind, and there's one thing that could happen in the season finale that would do just that; if Arya and Sansa are actually fooling everyone and plotting against Petyr "Littlefinger" Baelish, it will turn Winterfell from the worst storyline since Dorne into one of the best.
The Starks would never let a weasel break up their wolf pack.
And it wouldn't exactly be out of left field if it turns out that the Stark girls have been faking their spats since reuniting. There have been plenty of clues that the drama between Arya and Sansa isn't what it seems! If you're not already convinced that the Starks are just pretending to have a rift in their relationship to get the upper hand over Littlefinger purely out of faith in the show, then you need to consider these pieces of evidence.
Clues that Arya and Sansa aren't what they seem
- They've each been vocal about distrusting Littlefinger this season: There have been individual moments for both Arya and Sansa this season focused on their mistrust of Littlefinger. Sansa tells Brienne, "I know what he wants," with a look of disgust, and warns Bran about not accepting gifts from Littlefinger because he always expects something in return. (Flashback to season six, when she tells Jon that "only a fool would trust Littlefinger.") Arya reacts with horror when she finds out that Littlefinger is in Winterfell. Clearly, neither of the Stark girls nurses any affection for Littlefinger, nor do they trust him as far as they can throw him.
- Sansa did a complete pivot in her treatment of Littlefinger: The eldest Stark daughter spends the first four episodes of the season barely bothering to disguise her disgust for Littlefinger, brushing off his advice and essentially rolling her eyes every time he shows up. But then when she and Arya begin having their arguments, she immediately begins confiding in Littlefinger, asking for his advice, and making him feel valued as her confidant. This could be stupidity, trusting somebody that she knows is untrustworthy . . . or it could be her way of making Littlefinger feel successful in driving the Starks apart, steering Sansa into his own realm of manipulation.
- Arya is sloppy at best when casing Winterfell: Arya Stark not only trains with the Faceless Men in the arts of secrecy, disguise, subtlety, and deceit for more than a year; she also spends a good portion of that time blind, learning to move quickly and quietly, observing without drawing attention to herself. So when she essentially stomps a few paces behind Littlefinger to discover the note from Sansa that he hides in a mattress, it seems uncharacteristic at best. It seems reasonable that Arya might be intentionally sloppy to make Littlefinger think that she is falling for his plot, when really she is setting a trap of her own.
- Sansa never actually failed the "game": When Arya confronts Sansa in episode six, she tells her that they're playing a game wherein she will judge whether Sansa lies to her. Aside from some weird death threats, drudged up family drama, and sexist insults hurled between them, nothing actually comes of this "game," which would indicate that Sansa didn't lose. That's why Arya passes off Littlefinger's dagger, as a sort of prize; she recognizes that Sansa is still on her side and is equipping her to finish the job without ever discussing it outright (where Littlefinger might overhear).
- The significance of Brienne's oath is revisited: In both episodes five and six, Brienne is reminded that she swore an oath to protect each of the Stark girls, and Sansa sends her to King's Landing as a proxy. Could this be to stop Brienne from intervening in a situation that she might misinterpret, like a faux feud between the two sisters, or step in to protect them when they enter a dangerous scenario like attempting to murder Littlefinger?
- There have been exaggerated, outright lies between them: Certain aspects of Sansa and Arya's fights seem petty at best, while some are outright untruths. Arya accuses Sansa of smiling and standing by while their father was executed when she actively watched Sansa scream and fight as the order was given; this exaggerated accusation could be a way of boosting the drama between the sisters for Littlefinger's benefit if he is listening to their arguments from the shadows.
- It's all in the eyes: There have been a few telling glances during the Winterfell storyline this season. "When Arya reminds Brienne that's she's sworn to both of Cat's daughters, Sansa looks pointedly at Littlefinger," writes one Reddit commenter about the episode four scene. "When the fight concludes, Arya looks up to Sansa and [Littlefinger]. Sansa again glances pointedly at LF before walking away."
- "The lone wolf dies, but the pack survives": One of the most chilling parts of the season seven promos is this quote from Sansa Stark, which doesn't happen in episodes one through six. It can be deduced that Sansa will utter this sentiment in the finale, perhaps to Littlefinger, telling him that though he tried to separate her from Arya and Bran (rendering her a lone wolf), he failed, and now, she and her family (the pack) will survive by sticking together and killing off those who wish them harm. Bye-bye, Littlefinger!
Did Littlefinger really think that the Starks, who have been through so much, would let a weasel break up their wolf pack? As if! Now all that's left is to find out whether it will be Arya or Sansa holding the dagger when Littlefinger finally meets his long-anticipated demise.