He Shall Thunder in the Sky:
Intrepid archaeologist/sleuth Amelia Peabody and her family, back in Egypt in 1914 for another season of archaeological excavation, become caught up in the political turmoil sweeping the country, and when an exquisite artifact from a Giza dig is found where it ought not be, Amelia realizes her villainous arch-nemesis Sethos is at work.