Ghost talkers

"Ginger Stuyvesant, an American heiress living in London during World War I, is engaged to Captain Benjamin Harford, an intelligence officer. Ginger is a medium for the Spirit Corps, a special Spiritualist force ... Ginger and her fellow mediums contribute a great deal to the war efforts, so long as they pass the information through appropriate channels. While Ben is away at the front, Ginger discovers the presence of a traitor. Without the presence of her fiancé to validate her findings, the top brass thinks she's just imagining things"--Amazon.com.