Tad is a construction worker who dreams of being an archeologist like his hero, Max Mordon. When Max invites Tad to accompany him on an expedition to Peru, Tad jumps at the chance. However, things don't go as planned and Tad inadvertently sets off a booby trap, revealing an ancient tablet that leads to the location of the Emerald Tablet, a mystical artifact that can grant unlimited power to its possessor.
Max is kidnapped by a rival archeologist, Kopponen, who seeks the Emerald Tablet for himself. Tad teams up with Max's assistant, Sara, and a talking mummy named Jeff, to rescue Max and prevent Kopponen from obtaining the tablet. However, Tad's bumbling nature and lack of archeological knowledge continue to cause problems.
As they journey from Mexico to Chicago to Paris and eventually to Egypt, Tad and his friends encounter a variety of obstacles, including a monster made of sand, a furious bull, and a treacherous colleague of Kopponen's. Along the way, Tad gains confidence and Sara begins to see him in a more positive light.
In the end, Tad and his friends confront Kopponen in a final showdown at an ancient temple in Egypt. Tad uses his knowledge of construction to disable Kopponen's army of robots while Jeff and Belzoni (Belzoni being a character we learn of later) disable the temple's booby traps. Tad manages to obtain the Emerald Tablet and destroy it before it falls into the wrong hands, saving the world from potential catastrophe.
Tad returns to his construction job but is content knowing that he was able to live out his dream of being an archeologist and making a difference in the world.