Original: Vivian Ashe (Jamie Lee Curtis) leaves her pet chihuahua Chloe (Drew Barrymore) with her irresponsible niece Rachel (Piper Perabo).
Simplified: The movie is about a spolied chihuahua from Beverly Hills named Chloe (voiced by Drew Barrymore). Her owner, "Aunt Viv" (Jamie Lee Curtis), has to go to Italy, so she leaves Chloe with her niece, Rachel Ashe Lynn (Piper Perabo).