The Adventure of the Musgrave Ritual

Reginald Musgrave, a school friend of Holmes, saw his butler searching through private family papers. The butler Brunton got caught red handed with an ancestral ritual of the Musgraves as well. The ritual seemed worthless to the family but Brunton was determined to decipher it. A few days after Brunton disappeared.
"The Adventure of the Musgrave Ritual" is a part of "The Memoirs of Sherlock Holmes".