Ray and Sal are two orphan sisters that dream of having a dog and a family. While playing near the side of the road a mysterious van stops with a flat tire. The van is stuffed with stolen goods including valuable artworks. The burglars, Kosh and Wesley discover a stowaway, Great Dane puppy. They leave the puppy behind, and they drive off. A semitruck barrels down the road towards the pup. Sal quickly springs into action, narrowly rescuing the puppy. Back at the Orphanage the sisters decide to name him Chestnut. But they must keep him hidden from the Nuns, especially Mother Agnes, who strictly enforces a no-pets rule. The plot thickens when Ray, Sal, and Chestnut learn they are being adopted by a couple in New York City.