Amen Corner, London, 1864.
Orphan Sarah O'Reilly disguises herself as a boy so she can work in the offices of London's daily newspaper. She is soon befriended by Lily Korechnya, a wealthy widow and journalist. When Lily is enlisted to catalogue a wealthy socialite's magnificent jewel collection, she is intrigued by a fiery red diamond said to exert an unsettling influence over anyone who touches it.
Then two gruesome murders take place and Lily and Sarah set about uncovering the secrets of the ninth stone...
First published as The Ninth Stone, The Secret of the Ninth Stone has been revised and updated by the author.