Sherlock Holmes Season 1

Mr. Holder, a city banker, is Holmes' latest client. A prominent customer left him a beryl-encrusted coronet as a surety against a loan. Mr. Holder took the coronet home for safekeeping and was shocked to find his son Arthur attempting to deface it. Holmes deduces that Arthur is innocent and was only trying to cover up for another family member who has been duped by a smooth-talking thief.