Sherlock Holmes has left London on what was to become his Great Hiatus from 221b Baker Street. On the first leg of his journey, Holmes becomes embroiled in murder and assassination before even reaching the Port of New York. The mystery revolves around the long-dead Giuseppe Garibaldi, Italian revolutionary hero. Garibaldi's legacy, kept in The Witch's Box, if found and used by the wrong hands could start a world war. Back in London, Mycroft Holmes enlists Doctor Watson in a "problem" involving the disappearances of former members of Watson's own 66th Berkshire Regiment. Watson must determine whether the kidnappings of his old comrades-in-arms endanger Queen Victoria, Empress of the British Empire.