The document provides a summary of the plot of George R. R. Martin's novel "A Game of Thrones":
1) The story is set in the Seven Kingdoms of Westeros following a previous civil war known as the War of the Usurper.
2) The war was sparked by Prince Rhaegar Targaryen kidnapping Lyanna Stark, angering her family and betrothed Robert Baratheon.
3) Lyanna's father and brother were executed by the Mad King Aerys II Targaryen, leading Lyanna's brother Eddard and their friends Robert Baratheon and Jon Arryn to declare war against the Targaryens.