A Feast for Crows
Princess Arianne Martell, convinced her father Doran is a man of inaction who wishes to elevate her younger brother Quentyn Martell to rule Dorne, enacts a plot to crown Princess Myrcella Baratheon as queen. This fails due to a traitor in her conspiracy and Myrcella is disfigured in the process by Darkstar, Ser Gerold Dayne.
While Arianne is imprisoned, Doran confides that he hoped Quentyn would rule Dorne whilst Arianne would become Queen, as she had secretly been promised to the now-dead Viserys Targaryen in an effort to undermine those who lead to Elia's death. His new plan is to have Quentyn travel across the narrow sea to meet Viserys's sister, Daenerys Targaryen, and wed her instead.
A Dance with Dragons
Doran convinces Arianne and Oberyn's bastard daughters, the Sand Snakes, to work with him. Obara Sand is to guide the investigating Ser Balon Swann of the Kingsguard to hunt Darkstar. Doran reveals that Cersei was plotting with Balon to have Trystane murdered en route to King's Landing with Myrcella and to frame Tyrion Lannister.
Nymeria Sand is sent to take up the Dornish seat on the small council, while Tyene Sand follows her to King's Landing disguised as a septa, with the hopes of befriending the new High Septon. It seems likely that Sarella Sand is in Oldtown, disguised as a boy training to become a maester of the Citadel.