The Cairo Diary — Maxim Chattam

British-occupied Cairo, 1928: Several young children have disappeared and were then found, horribly mutilated, in the tombs just outside the city. Panic is spreading among the locals after a cloaked giant is sighted. Has a ghoul from One Thousand and One Nights been brought to life? British inspector Jeremy Matheson follows the trail of the monster, which takes him into the depths of underground Cairo, as well as deep into his own tortured past.
Mont-Saint-Michel, 2005: Marion has taken refuge in the wind-swept and remote monastery located on a spit of land on the west coast of France. In the wake of a scandal, caused by her own revelations, that is now reverberating through the French capital, she has been spirited away from Paris and brought here by the French Secret Service for her own protection. When she finds a diary dating from 1928 in the monastery library, penned by Jeremy Matheson and hidden inside the jacket of an Edgar Allan Poe book, she is inexorably pulled into the past as she follows his investigation. Soon she feels she is being watched, and taunting notes and riddles urge her to give back what is not hers. Could one of the brothers or sisters at the monastery be behind this? And who is the old man Marion befriends?