The White Walkers have left the Lands of Always Winter, they attacked Jon Snow and his band of Night’s Watch and Wildlings in Hardhome. They are marching closer every day to The Wall, where they will attack Castle Black in Season 6, and we know somehow with the help of the Wights, the Army of Dead Men they control, they will somehow bring at least a part of The Wall down and venture South into Westeros, where Winter will reach King’s Landing and Dorne.
The Night’s Watch almost don’t believe the threat is as great as it is. Fans remember seeing Hardhome, and now they fully realize why Winter is Coming was such a perilous phrase that we heard for five seasons. The White Walkers will also bring with them packs of ice spiders as big as hounds. The last Long Night was 8,000-years ago, and Winter lasted past a generation. It’s here again, the White Walkers are out of hibernation and all hell is about to break loose, as we see in the video preview below: