The mummy Imhotep needs the Manacle of Osiris to fulfill his quest to rule all mankind, but it's stuck on Alex's wrist, and only the Lost Scrolls of Thebes can remove it without destroying its power.
A clue about the scrolls in the diary of Alexander the Great takes the O'Connells into the Egyptian desert, where they encounter Imhotep, who is also searching for the same palace.
En route to Australia, the heroes crash-land on a small tropical island, summoning a long-dormant lava creature that pushes the local volcano toward eruption.
In an effort to locate the scrolls, Weasler and Imhotep kidnap Albert Einstein, and it's up to our heroes to save the genius before he shares any valuable information.
A vision takes the family to a mountaintop in Peru, where they meet the legendary Cloud People and the Native American spirit that protects the area from outsiders.
While in China, Alex befriends the young emperor of the Forbidden City, who promises to help find the lost scrolls - but instead accidentally unleashes a demon dragon.
The search is on for the three pieces of the Puzzle of Horus, which may lead the O'Connells to the Scrolls, but first they must battle Imhotep, Weasler and a giant sandworm.
Alex begins his Medjal training with Ardeth Bay and later learns that Imhotep is not only alive but is also planning to resurrect his long-lost love, an evil high priestess named Anck Su Namun.
The Eye of Shiva, a prismatic egg that can turn the skies to fire, goes missing from a temple in Sri Lanka, and the heroes tract it to the Chicago International fair.
Jonathan and the O'Connells travel to Thailand to search for a missing friend and discover that Anck Su Namun has used the Ring of Sukothai to drain the life force out of the woman.
Imhotep and Weasler discover a centuries-old Medjai journal that leads them to "the Medallion of the Medjai", an ancient artifact whose power rivals that of the Manacle of Osiris.