A Feast For Crows by George R. R. Martin

A Feast For Crows is the fourth of seven planned novels in A Song of Ice and Fire, an epic fantasy series by American author George R. R. Martin. The novel A Feast For Crows was first published on 17 October 2005 in the United Kingdom, with a United States edition following on 8 November 2005.
The War of the Five Kings is coming to an end. Robb Stark, Joffrey Baratheon, Renly Baratheon, and Balon Greyjoy are all dead, and King Stannis Baratheon has gone to the aid of the Wall, where Jon Snow has become Lord Commander of the Night's Watch. King Tommen Baratheon, Joffrey's eight-year-old brother, now rules in King's Landing under the watchful eye of his mother, the Queen Regent Cersei Lannister. Cersei's father Tywin is dead, murdered by his son Tyrion, who has fled the city. With these two men gone, as well as no longer having to deal with Joffrey, there are no more checks on Cersei and she is essentially Ruling Queen of the Seven Kingdoms in all but name. Now that Cersei finally stands at the height of power and her enemies are scattered to the winds, in a grim irony it quickly becomes clear that she is incapable of wielding the power she has killed and manipulated so many to acquire, and she spirals into self-destruction.
Meanwhile, Sansa Stark is still in hiding in the Vale, protected by Petyr Baelish, who has secretly murdered his wife Lysa Arryn and named himself Protector of the Vale and guardian of eight-year-old Lord Robert Arryn... (Summary by Wikipedia)