The Girl Behind The Glass by April Grace

What if Snow White had a stepsister?

Winnie is the daughter of the mayor of the cursed Mirror Village, Cranwick. She has always felt trapped, since her city is controlled by the brutal Roth witches, and the only way out of the city is through their mirror portals.

Princess Frost is the lonely princess of Icefall, the Winter kingdom. She has felt abandoned since her mother's death five years ago, especially since, for the last three years, he has been courting a princess that she knows nothing about.

From different sides of their world, when Winnie's mother starts to become secretive, sneaking around the city and talking to the witches through the mirrors, Winnie and Princess Frost each uncover a trail of her secrets. Winnie's mother has found herself trapped into a forced marriage with the Winter king, soon to become Princess Frost's stepmother, in order to find a cure for Winnie's father's sickness.