1873. Known worldwide for her talent in conjuring the spirits of murder victims to ascertain the identities of the people who killed them, acclaimed spiritualist Vaudeline D'Allaire is highly sought after by widows and investigators alike. Lenna Wickes has come to Paris to find answers about her sister's death, but to do so, she must overcome her own logic-driven bias against the occult. When Vaudeline is beckoned to England to solve a high-profile murder, Lenna accompanies her as an understudy. As the women team up with London's exclusive Seance Society, they begin to suspect that they are not merely out to solve a crime, but perhaps entangled in one themselves.