When mummies go missing all over London, eleven-year-old Theodosia puts aside her fight against the Serpents of Chaos to save her father, who is suspected in the thefts, all the while avoiding a string of new governesses.

"Theodosia sets off to Egypt to return the Emerald Tablet- a tablet embedded with the knowledge of some of the ancient world's most guarded secrets. Accompanied by her cat, Isis (smuggled along in a basket), Theo plans to return the artifact, then explore the mysteries surrounding her own birth, and- oh, yes- help her mother dig up treasures on her archaeological expedition. But nothing ever works out as planned, especially when a precious treasure...