We've spent the past five seasons knowing that winter is coming on Game of Thrones. But a new fan theory suggest that Sunday's season 6 finale might be the episode that winter (and the White Walkers) finally hits Westeros with a vengeance.Logistically, the White Walkers are running out of things to do. There are only so many communities to torment north of the Wall, so their eventual push south makes sense as a plot device. Moreover, not many in Westeros (and even fewer in King's Landing) even believe the White Walkers have returned from their centuries-long absence. Sunday's season finale is called "The Winds of Winter," and there's a good chance the White Walkers will be a part of that wind. At Mic , Miles Surrey brings up an intriguing fan theory for how the White Walkers' arrival could happen. When Bran was touched by the Night's King during the White Walkers attack on the Three-Eyed Raven's cave in episode 5 , an ancient (and somewhat unexplained) magic was broken. That single touch allowed the White Walkers to locate Bran and break the magical barrier that kept them from getting into the hideout.Now that he's with Uncle Benjen (a.k.a. Coldhands) , it's likely that Bran will return to Castle Black or, at the very least, make it to the Wall. The bond between Bran and the Night's King could persist, making anywhere Bran goes vulnerable to an attack by the White Walkers.