Skip this if you're familiar with the setting.
A Song of Ice and Fire is a fantasy epic game set in the world envisioned by George R. R. Martin, a compelling hodgepodge of unique low-fantasy concepts and an interesting take on a medieval world with different circumstances and influences then our own.
There is Westeros, a vast continent stretching from the sun-seared desert country of Dorne in the south to the endless frozen tundra beyond the Wall (a world-wonder not unsimilar to the Great Wall of China, except made of solid ice and patrolled by a strange mix of the desperate, the noble, and the wicked) in the north. It's home to the Seven Kingdoms, united beneath the Iron Throne by alliance and conquest, and as you might expect, countless intrigues and clashes - getting worse all the time since the last of the dragons died, the lineage of their ancestral keepers and kings of men dying out with them. The land is steeped in history, from stories of the laughing druids known as the Children of the Forest and their battles against the cruel and alien race known as the Others, to its settlement by the barbarian First Men, its conquest by the faith-guided Andals, its re-conquest by the Valyrians and their terrible dragons...
In the present day, that ancient glory has faded into the past. The world has begun to forget magic, and relegated banished evils to the realm of myth and legend. Even the dragons have died. It's a new era, one of sword and dagger - warfare conducted across open fields and behind closed doors, where men strive against men to hold together a failing legacy or to cut away a large enough piece to make their own future with. Fables of dragons cannot cook men in their armor. Songs of the Others' icy terror cannot unify divided peoples, not even the disparate factions of the Night's Watch sworn to watch the North for their return. The tales told of the Children of the Forest are amusing pastimes, but all that is left of their magic are the faces carved into the weirwood trees, mute and blind to all appearances. The age of wonder is gone.
Or so it is said by any number of fools.
Resume reading here.
Westeros is essentially an enormous, self-contained playroom carefully structured to include every kind of terrain imaginable, a history so vast and complex you could run dozens of totally dissimilar games out of it without once breaking canon, and enough empty space to dredge entire homebrew settings out up of without needing to change what's already there.
We're going to play in it.
You don't really need any familiarity with the books beyond SIFRP - it'll help, but they give you plenty to go on, and I've already decided to do quite a bit of trampling over Martin's beautiful epic - it's a great read, but despite all the lore it's a character drama, and someone else's character drama is rarely a good setting for your own. Just bring your imagination and your A-game, and we'll have adventures to go on in spades.