Matilda and Edgar are in London's haunted theatre-land, where Matilda is rehearsing the all-new Signora Valentina show and Edgar is training to become a poltergeist. Spooks are everywhere in this city, and it isn't long before Lockett & Wilde are called upon to investigate strange happenings at a local curiosity shop. Soon, they are drawn into the unsolved case of the infamous gold thief, Bullion Bill, and Matilda finds herself investigating the story of her own parents' death. The ghosts of London know the truth, and Lockett & Wilde won't rest until they find it out.