The Adventure of Musgrave Ritual

Reginald Musgrave finds his butler reading an ancient family document entitled "The Musgrave Ritual". The butler begs the owner to quit himself and he receives the agreement but the very next day he disappears without any warning not even taking his things. A maid disappears after him, the one whom with the butler used to have a love affair. Musgrave asks Sherlock Holmes to open the secret of the mysterious disappearances.