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). Rachel and her friends go on vacation to Mexico, and Chloe gets dognapped by an evil Mexican dognapper who at first wants to use her in dog fights but sees her value and wishes to put her at randsome (have the owners have to pay money to get her back). In the meantime, Papi (voiced by George Lopez), a male chihuahua who is in love with her is on the lookout for her. Chloe makes friendship with a lonely German Shepherd named Delgado (voiced by Andy Garcia) who travels with her to protect her from the evil Doberman (voiced by Edward James Olmos) who wants to kill her and steal her diamond collar to return it to the dognapper who owns him.