THE ADVENTURE OF THE MUSGRAVE RITUAL by Sir Arthur Conan Doyle

Reginald Musgrave visits Holmes after the disappearance of two of his domestic staff, Rachel Howells, a maid, and Richard Brunton, the longtime butler. Brunton vanished without his belongings after being dismissed for secretly reading a family document, the Musgrave Ritual. Brunton's former lover, Rachel Howells escaped through a window after being hysterical abour Brunton's missing. Her footprints led to the edge of the mere, and ended there. Musgrave had the mere dredged, but only a sack containing some rusty, mangled bits of metal, and some coloured stones or glass were found. Holmes looked upon the case not as three mysteries, but as one.