Carter and Sadie have nothing in common but their parents: their father Dr. Julius Kane, a brilliant Egyptologist, and their mother, a famed archaeologist who died under mysterious circumstances when they were young. The siblings barely know each other, but one night, their father brings them together at the British Museum, promising a 'research experiment' that will set things right for their family. His plans go horribly wrong. An explosion unleashes an ancient evil - the Egyptian god Seth who banishes Dr. Kane to oblivion and forces the children to flee for their lives. Now orphaned, Carter and Sadie must embark on a dangerous quest - from Cairo to Paris to the American Southwest, to save their father and stop Seth from destroying everything they care about.