With the Brotherhood persecuting witches like never before, a divided Sisterhood desperately needs Cate to come into her Prophesied powers. And after Cate's friend Sachi is arrested for using magic, a war-thirsty Sister offers to help her find answers if Cate is willing to endanger everyone she loves. Cate doesn't want to be a weapon, and she doesn't want to involve her friends and Finn in the Sisterhood's schemes. But when Maura and Tess join the...