Margaret Prior is spiraling into spinsterhood and has just failed at an attempt at suicide. As part of her recovery she is to act as a visiting lady at Victorian London's Millbank women's jail. Here she is enthralled by one Selina Dawes, a recondite spiritualist imprisoned after hosting a seance that left an elderly woman dead. What ensues upon this union is an ever twisting game of 'Do you believe?'. Waters is in pristine form in this haunting, bleak, and pearl-clutching mystery.