When Sarah, Helen and Evie return for the summer term to Wyldcliffe, there is tension within the sisterhood. Evie seems to have turned her back on the Mystic Way and Helen is distracted by her still-unresolved feelings about her mother, Mrs. Hartle, who is now dead but exists as a dark spirit. Sarah is lonely and unsettled. Unlike Evie, she wants to find out more about her own Mystic powers and her strong connection to the earth.

A new girl at Wyldcliffe, Velvet Romaine, is creating trying to stir up trouble. Velvet is a wild child who has been expelled from a string of boarding schools, and in desperation her parents have sent her to strict, traditional Wyldcliffe. Velvet gets a crowd of girls to sneak out of school for a “May Rite,” and unknowingly summons and releases a power – the Priestess. Mrs. Hartle’s dark spirit is now free to take revenge on the girls.