Forced to accompany their parents on their honeymoon in Spain, new stepsisters Amy and Felix find the animosity between them escalating especially when Felix's boasting about family wealth to a stranger results in the kidnapping of the girls and their little brother.
After his father remarries, twelve-year-old Jeremy begins to feel that there is no place for him in a family which now includes a stepsister his age who is a superb athlete.
The mummy that Andrew creates for his fifth grade project seems to have special powers and helps him to understand his feelings about himself, his dead mother, and his stepbrother, who he calls Mr. Gifted.