Lord Eddard Stark has been killed by the command of King Joffrey and his daughter Sansa is held as a hostage. Sansa's sister Arya is making her way north, toward her family's home, Winterfell. And, in Winterfell, Eddard Stark's eldest son Robb has declared himself King in the North and joined the fight for the Iron Throne now that the old King, Robert, is dead.
When I said this book was long I wasn't kidding you- the print is small and there are almost a thousand pages, the next book in the series being a few hundred pages longer than that, but I have read it twice and feel it is well worth the effort. I read the first book in the series, A Game of Thrones, on the recommendation of a friend, and went on to read up to book four, A Feast for Crows. A Game of Thrones was chosen for a book discussion group at my school last year- the first time a piece of fantasy was ever chosen- and we are considering doing A Clash of Kings this year.
Lastly, you have to read A Game of Thrones before reading this book because I doubt you would have any idea what was going on if you did not, and nine hundred pages of confusion could get really dull.