In this fourth book in the series, Theodosia sets off to Egypt to return the Emerald 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 archeological expedition. But nothing ever works out as planned, especially when a precious treasure appears suddenly, and then just as suddenly disappears . . . When the Serpents of Chaos get involved, Theo finds she's digging up a lot more than she expected!