Clark thought he knew what grief was. Addie thought she understood the dangers of the Tempest Sea. They couldn't have been more wrong. When their only chance at survival lands them on opposite ends of an island that shouldn't exist, they will both be forced to contend with the consequences of their latest mistakes--and each other's. Will they be able to keep the promises they made one another, even as loss and circumstance morphs them into the very people they never thought they would be? Or will their relationship be the next casualty in this never-ending battle?