After a tragedy almost too painful to bear, Lily Albrecht feels herself lost, adrift and resigned to her quiet life as a rare book dealer. Until she gets a lead on 'The Book of the Most Precious Substance', a 17th century manual rumoured to be the most powerful occult book ever written, if it really exists at all. With some of the wealthiest people in the world willing to pay Lily a fortune to find it, she embarks on a journey from New York to New Orleans to Munich to Paris. But will Lily's quest help her find some answers, or will she lose everything searching for a ghost?