Arya Stark is without a doubt one of the most beloved characters in "Game of Thrones." But even the hard core Arya fans noticed that there's something off about her ever since that cold opening in the season seven premiere when she poisoned the entire Frey family. At that point, we all thought Arya had become a cold blooded assassin, with nothing but revenge on her mind. This comes as no surprise as she witnessed the beheading of her father and the Red Wedding massacre where her mother and brother were killed.

Arya's real purpose

Fortunately, after that cold opening scene, Arya proved that she is not all lost when she spared those Lannister soldiers.

But her real purpose came in the later episodes when she learned that the Starks are back at Winterfell. Also, that touching reunion with Nymeria played a crucial role in showing Arya that she needs to become part of the pack again. And even though her reunion with Sansa and Bran wasn't as warm as we expected, she did show that she still cares.

Arya's strange behavior

Just when we thought that nothing could stop the Starks, things started to fall apart. It all began when Arya overheard that Sansa is not standing up for Jon in front of the Lords of the North and the Vale. Then, a conflict went even deeper when Arya found Sansa's letter. And even though she was well aware of the fact that Sansa was forced to write that letter, that didn't stop Arya from behaving like a little brat.

She even went as far as to threaten Sansa before eventually giving her the Catspaw dagger. And the fans were left in shock, wondering what was that all about.

What is Arya up to?

Reddit user Tartandrake theorize that was all part of Arya's plan. After learning that Sansa is thinking about overthrowing Jon so she could have all the power, Arya needed to convince her sister that family comes first.

The plan is to have Sansa realize the importance of sticking together and that she needs to be "all in" when it comes to family, without any hidden agenda. And giving her the Catspaw dagger was Arya's way of saying "Now is your chance to prove your loyalty to the family."

The theory further suggests that Arya knew all along about Littlefinger's intentions and she wants Sansa to get rid of him once and for all.

Perhaps it will take a little bit of help from Bran for Sansa to realize that Littlefinger is the enemy. And that "a lone wolf dies, but the pack survives" line from the trailer could be Sansa finally realizing that family is the only thing that matters.