O Jerusalem

O Jerusalem is the fifth book in the Mary Russell series by Laurie R. King. It is set during Mary Russell's and Sherlock Holmes's voyage to the Holy Land, and the action takes place chronologically during the events of The Beekeeper's Apprentice.

Russell is nineteen in this book and on a break from studying theology at Oxford. During the operation she is disguised as a young Bedouin man, has to learn Arabic as she goes, keeps throwing knives in her boots and, according to the character description, has excellent aim. That combination of an untrained academic and a functioning field agent is the novel's running tension.

The plot is counter-intelligence in a specific historical moment. The guides Mahmoud and Ali Hazr are not what their appearance suggests, and their aim is to prevent a plot against the British in Jerusalem while General Allenby's administration takes shape. Because the book sits inside the chronology of the first novel, it fills in a period the series had skipped rather than advancing the later timeline. Allenby's administration is still taking shape, so a plot against the British is exactly the kind of threat a new authority is least able to see.