Fear may be our only hope

Three of the groups with our favorite main characters. Elsa and Kristoff and Anna end up in Storybook. Emma and her family are in the enchanted forest. While Cary and her new boyfriend and her friends, are going to world with no magic. Who is the villain to put all these three groups in different places? Will there be a new hero? And why must these three groups be not the rest? Or will there be the rest?