A few days before Christmas, Sherlock Holmes is bored - until Inspector Lestrade brings a baffling case: a young novice has been found dead in the Abbey of the Saviour just outside London. On the way there an avalanche buries the police van, and Holmes, Watson and Lestrade find themselves snowed in with the monks of the abbey - one of whom is a murderer. Secret passages, forbidden books, a hidden laboratory and a missing young woman lead the detectives to a plan so monstrous that it reaches for the blood of the Messiah himself. This radio play was produced with the help of Eleven Labs and using properly licensed voice clones, and was checked by human proofreaders.