Breaking the Suun - Legends of the Fallen, #5

Frida knows she's not what others think. But she's the only one who knows the truth. The enemy now knows that Frida is Onen Suun's heir. She's reported to be the only person who can seal the prison and keep Dag'draath confined. But Frida knows the secret, the truth that no one is willing to repeat. She's not the heir. While she's desperately trying to locate the real heir, to find a real solution to keeping the prison closed, Dag'draath and his armies are rallying to kill her.
It's going to take all of her might, all the experience of her siblings, and the skills of their elven prince to keep her alive. Before the Suun heir is broken.