A Storm of Swords literally stars where A Clash of Kings completed and is book 3 in the game of thrones PDF series. The Seven Kingdoms is currently at war with the Stannis Baratheon, Balon Greyjoy, Joffrey, Robb Stark fighting fervently to secure their crowns. It should be noted that Renly Baratheon is dead already.
Stannis Baratheon’s failed in his attempt to take the King Landing because of an alliance between House Tyrell and Lannister, even House Martell offered up their resources to the Lannisters. Unknown to them though there is a army of wildlings approaching the Wall of Mance Rayder. The Night Watch is a very small force therefore they are virtually unstopped in their assault. In the East Danery Targaryen, is hoping to gather an army to attempt a coupé on the Iron Throne she is returning from Pentos.