The Musgrave Ritual

"The Musgrave Ritual" is a short story by Sir Arthur Conan Doyle, featuring his fictional detective Sherlock Holmes. The story was originally published in Strand Magazine in 1919, and was collected later in The Memoirs of Sherlock Holmes. Unlike the majority of Holmes stories, the main narrator is not Doctor Watson, but Sherlock Holmes himself. With Watson providing an introduction, the story within a story is a classic example of a frame tale. It is one of the earliest recorded cases investigated by Holmes, and establishes his problem solving skills.
In the story, Holmes recounts to Watson the events arising after a visit from a university acquaintance, Reginald Musgrave. Musgrave visits Holmes after the disappearance of two of his domestic staff, Rachel Howells, a maid, and Richard Brunton, the longtime butler. The pair vanished after Musgrave had dismissed Brunton for secretly reading a family document, the Musgrave Ritual. The Ritual, which dates from the 17th century, is a riddle set in question/response form.