The Wicked Ones by Robin Benway

"Blood is blood...and one way or another, we all bleed." Drizella and Anastasia only know one thing for certain: they will never end up like their mother, Lady Tremaine. When their father left them as young girls, he took what was left of their family's fortune and their mother's dignity with him. A few years and one deceased stepfather later, the only version of Lady Tremaine that Drizella and Anastasia know is a bitter and cruel head of house. Anastasia and Drizella have promised themselves—and each other—that they'll be different. They'll find love, see the world, and never let their hearts go cold. But both sisters are all too aware of what it can mean when cast into disfavor with their mother, and fueled by Lady Tremaine's tendencies to pit the daughters against one another, Drizella and Anastasia are locked into a complicated waltz of tenuous sisterhood. On the cusp of the royal debut party—their one chance to impress the Prince and live up to their mother's expectations—the...