In F. Paul Wilson's "The Adventure of the Abu Qir Sapphire," an aging Holmes must help an archaeologist clear his name when he is framed for stealing the Abu Qir sapphire by the mysterious Madame de Medici, whom Holmes previously encountered in 1879. They trace her to the Limehouse residence of Zani Chada. In both a flashback to 1879 and the present day, Madame de Medici writes Holmes a four-line letter after their encounters. The first lines of each letter spell out "SREM," and Holmes believes they contain a clue to her identity. Madame de Medici is from Sax Rohmer’s stories “The Key of the Temple of Heaven,” “The Black Mandarin,” and “The Treasure of Taia.” Zani Chada was arrested by Chief Inspector Red Kerry in Rohmer's “Kerry’s Kid,” set in 1921. In “The Key of the Temple of Heaven,” set in 1922, Madame de Medici was temporarily living in Chada’s former house. The house later passed to Burma Chang, who was murdered in Yellow Shadows. The Compendium of Srem is an occult tome from Wilson’s Repairman Jack series. Madame de Medici went up against Jack and Heather Graham’s P.I. Michael Quinn in Wilson and Graham’s story “Infernal Night.”
The other two crossover stories are both AUs. In Duane Swierczynski's "Tough Guy Ballet,"set in December 1987, an L.A.P.D. detective apprehends a serial killer whose M.O. differs every time with the help of a teenage girl. As it turns out, both the murderer and the girl are possessed by the souls of others. In the girl’s case, she bears the soul of not only the cop’s partner, who was murdered by their quarry, but several other cops and detectives, including “this big fat guy who’s obsessed with orchids, and some alcoholic lady named Nora, and this British guy who plays the violin and seems to know everything about everyone..." The British guy is Holmes. The orchid enthusiast is Nero Wolfe, while Nora is Nora Charles from Dashiell Hammett’s The Thin Man. Holmes’ last recorded appearance in the CU is the 1986 comic book story “The Doomsday Book,” in which he meets Batman and Robin, the Elongated Man, and Slam Bradley. Since it seems probable a future crossover pastiche will have Holmes alive even later, I am counting this as an AU.
In Zoe Sharp's "Hounded," Sharp’s series character, ex-soldier turned bodyguard Charlotte “Charlie” Fox, becomes involved in Sherlock Holmes’ investigation of the Hound of the Baskervilles when Beryl Stapleton’s mother hires her to rescue her daughter from her husband Jack. This story updates Doyle’s tale to the twenty-first century, with Watson blogging about Holmes’ cases and serving in Iraq as well as Afghanistan.
These crossovers are only three of hundreds covered in my book Crossovers Expanded: A Secret Chronology of the World Volume 3, which will be published by Meteor House! All three volumes are AUTHORIZED companions to Win Scott Eckert's Crossovers: A Secret Chronology of the World Volumes 1 and 2!