 At the beginning of "A Game of Thrones", 15 peaceful years have passed since the rebellion led by Lord Robert Baratheon that deposed and killed the last Targaryen king, Aerys II "the Mad King", and proclaimed Robert king of the Seven Kingdoms, with a nine-year-long summer coming to an end.The principal story chronicles the power struggle for the Iron Throne among the great Houses of Westeros following the death of King Robert in "A Game of Thrones".Robert's heir apparent, the 13-year-old Joffrey, is immediately proclaimed king through the machinations of his mother, Queen Cersei Lannister.