The sign of nine
(Book)

"Warlock Holmes may have demons in his head, but now Dr. John Watson has a mummy in his bloodstream. Specifically that of the sorcerer Xantharaxes, who, when shredded and dissolved in a seven-percent solution, produces some extremely odd but useful prophetic dreams. There's also the small matter of Watson falling for yet another damsel-du-jour, and Warlock deciding that his companion needs some domestic bliss..."--Provided by publisher.