A quiet and shy high school student, Cassie, moves with her mother from sunny California to the gloomy town of New Salem, to live with her grandmother, who is passionate about mysticism and strangely knows a lot about herbs. At first, Cassie misses home and her old friends, but soon becomes acquainted with a group of teenagers who keep the entire school in fear. They accept her into their secret circle, and after a special ritual, Cassie becomes part of a clan of powerful witches. And then Cassie falls in love, and she has to make a difficult choice: stay with her lover or step into the world of dark magic.