“Safe Custody” is an adventure novel written by Cecil William Mercer in 1932. Departing from his previous works featuring Richard Chandos, Mercer introduces new protagonists, John Ferrers and his cousin Hubert Constable. The story revolves around the inheritance of Castle Hohenems in Austria by Ferrers and Constable. They embark on a quest to locate the priceless carved jewel collection hidden in the castle's dungeons, once owned by the infamous Borgia Pope Alexander VI. Joined by Andrew Palin, the trio must outsmart the cunning thief Harris and his accomplice, Father Herman Haydn.