While the great Houses of Westeros fight with one another over who will sit on the Iron Throne, a foreign faction steadily grows in power across the sea. Daenerys Targaryen is uniting the Dothraki forces along with Khal Drogo. These horselords will soon be making the trek across the Narrow Sea and make their presence known. A new contender for the Iron Throne is about to enter in grand fashion.
The Free Folk in the north care not for the squabbles of the various Houses south of The Wall. These nomadic tribes will go where they please. And recently, they've been flowing their way into warmer climes. However, the people already in those lands don't take kindly to what appears to be an invasion force. Both sides are arming for war.