Every Game of Thrones fan is overjoyed now that Sansa and Arya Stark are together in Winterfell at long last, but there's still one dark cloud hanging over the sisterly reunion: Littlefinger. At the tail end of the episode (spoiler alert!), we see Littlefinger plant a seed of doubt between the two sisters, but exactly what did Alys Karstark whisper to Littlefinger? And why is it such a big deal?
Let's go over the quick, but definitely is going to be important, little scene. As per usual, Littlefinger is just working his away around Winterfell, wreaking his insidious little havoc, so of course the new arrived and newly assassin-trained Arya is going to tail him to see what he's up to. Basically, Arya witnesses a parade of whispers as Littlefinger scurries close to a bunch of people in Winterfell and sets his sure-to-be-evil plans into motion with his whispers.
In the end, Arya discovers Littlefinger has planted a note somewhere in Arya's room. Arya goes in and investigates, finally discovering the small scroll buried in a hole in Sansa's mattress. We don't get to see exactly what the note says — a quick glimpse reveals it's some message to Jon about the Lannisters — but it's definitely clear Littlefinger is up to some nonsense.
Aside from the note, it's also of interest to note who Littlefinger was whispering with in his conniving stroll through Winterfell. Arya witnesses him mumbling something with a girl named Alys Karstark in a doorway, and that could end up spelling trouble for the Starks. Though we don't hear what they're saying, Alys is the new leader of the Karstarks, a clan that had previously joined up with Ramsay Bolton to take over Winterfell. Although Alys pledged to Jon Snow her house's alliance with the Starks, they have a history of not getting along. Littlefinger could easily be stirring the pot for another takeover of Winterfell.
So, the question remains: Is he?