The year is 1917. Risking winter storms and German torpedoes, the Emersons are heading for Egypt once again: Amelia, Emerson, their son Ramses and his wife Nefret. Emerson is counting on a long season of excavation without distractions but this proves to be a forlorn hope.
Yet again they unearth a dead body in a looted tomb - not a mummified one though, this one is only too fresh, and it leads the clan on a search for the man who has threatened them with death if they pursue the excavations.
If that wasn't distraction enough, Nefret reveals a secret she has kept hidden: there is reason to believe that Sethos, master criminal and spy may be helping the enemy. It's up to the Emersons to find out, and either prove his innocence - or prevent him from betraying Britain's plans to take Jerusalem and win the war in the Middle East.