Beyond the Prophecy - Dual Magics, #3

The foundations of Vatar's world are unraveling. And being one of a handful graced-or cursed-with both kinds of magic makes Vatar a target. One member of the ruling Council sees him as an obstacle to furthering her power. Gerusa launches an unsanctioned attack on Vatar and his family. When that fails, she is forced to flee the city. But that's far from the end. Even from exile, Gerusa exerts influence, fomenting unrest and uncertainty.
She intends to unseat the Council and replace it with herself as sole-and despotic-ruler. Unable to trust the Council, Vatar sets out to stop her. If he's captured, he'll be forced to prove his boast that it's impossible to imprison anyone who can do what he can-or die.