Phoebe Halliwell is stunned to discover her half-sister Paige in her latest vision. The vision reveals that she is, in fact, an imposter who intends to destroy the Power of Three from within. Paige senses that her sisters' attitude toward her has changed, and when she meets Timothy McBride, an attractive young stranger, she decides not to tell anyone about him. Mutual secrets drive sisters apart at the most inopportune time. Women are dying all over the city from the intervention of supernatural forces. The criminal may be connected to the sisters' past, but if they cannot act together, then it is unlikely that they will be able to stop him...