Two little girls, Annie (Lindsay Lohan) and Holly (Lindsay Lohan), meet at summer camp. They looked strikingly similar, but they couldn't get along. Quite by chance, they found out that the other person was their twin sister. They began to inquire about each other's lives and discuss their parents: they met on a luxurious sailing ship and got married during the trip, but their relationship ended in a breakdown. Because of this divorce, one twin sister was brought to California by her father (Dennis Quaid) to live in a beautiful vineyard; the other was brought to London by her mother (Natasha Richardson), a wedding dress designer. The two never met or even knew each other existed. After learning the truth, the two naughty little ghosts began to plan their strategy: they decided to change their identities and live in each other's families. Everything was going well until their father was about to remarry, and the sisters started a crazy sniper war against their stepmother (Elaine Hendrix)...