Molly goes undercover at the Hudson River estate of Senator Barney Flynn to determine whether two visiting spiritualists are frauds. The senator’s wife hopes the sisters can contact her son, who disappeared during a notorious kidnapping, and Molly quickly concludes that the old case was never properly solved.
A séance produces disturbing information and new violence follows. Posing as an Irish relative, Molly questions the family and servants while trying to discover whether the mediums are exploiting grief or whether someone in the mansion is using them to conceal murder.