Elspeth and Isabella Stinson grew up with an ideal life. They enjoyed a close relationship with their parents and with each one another. Sadly, all of that is about to change. On their sixteenth birthday the twins find out they have a dark heritage. Their mother, Mabel Stinson, lied to her daughters about who she really was. It was a secret their mother's twin, Millicent Du Bois, was all too happy to unveil. Along with the secret revelation comes something else, a chance at special mystical powers. The twins are witches; one from the light and one from the dark. As Ellie and Izzy end up on opposite sides, they find their lives blown apart and perhaps forever changed.