Dragon Hunters (Chronicles of the Exile)

Once a year the Dragon Gate is raised to let a fabled beast pass into the Sabian Sea. There, the dragon will be hunted by the Storm Lords, a fellowship of powerful water-mages. Emira Imerle Polivar is coming to the end of her tenure as their leader, and has no intention of standing down. But Imerle is not the only one intent on destroying the Storm Lords, and when she sets her scheme in motion, that enemy uses the ensuing chaos to play its hand.