What follows is a mad dash to New York and Boston with a deranged Spiritualist medium on the tail of Holmes and his team of investigators: Wiggins, his feminist wife, and Rose Mackenburg, Houdini’s top investigator into phony Spiritualism, which was rampant at the time. In Boston, Sir Arthur introduces the team to Margie, the most highly regarded Spiritualist of the day. Her séance and the bizarre form of treasure hunt that follows leads to a stunning climax that will change everyone’s perception of Holmes’s character.
Sounds like fun. I especially like that Rose Mackenburg is a character in this book. Not sure why Margery is called "Margie," but, hey, it's fiction.
Purchase Who Done Houdini? by Raymond John at Amazon.com.