The story is about a chihuahua who gets dognapped in Mexico and has to escape from an evil Doberman . The plot centers around a Chihuahua , Chloe , who gets dognapped in Mexico and has to escape from an evil Doberman , El Diablo , with help from a lonely German Shepherd , Delgado , and a hyperactive male Chihuahua , Papi , who has a desperate crush on her .