Soon after arriving at her new home in Evreux Normandy Irene Adler is approached by a mysterious woman who mutters some strange words about Irene's mother being in danger - and then vanishes into thin air. It's just the first in a series of unsettling events that Irene Sherlock and Lupin must decipher. The three sleuths' questions will lead them to a secret crypt far beneath the streets of Paris and to an ancient relic that it is rumoured to be worth a fortune. But how far will they go to obtain the priceless treasure