Sherlock, Lupin, and me

Irene's family has moved to Evreux, Normandy. Soon after arriving at her new home, she is approached by a mysterious woman who mutters some strange words about Irene's mother being in danger, before vanishing 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...