Even though she is an orphan, there is nothing in the world Sally Ann (Makenzie Vega) wants more than a dog. She and her sister Ray (Abigail Breslin) pray for one each day, so when a pup is abandoned on the road outside the institution where they live, the girls are sure it is heaven sent. Suspecting the nuns who provide their care may not see the situation with the same appreciation, the pair decides to keep their miracle to themselves.
But the arrival of Chestnut (the name they give their pet) is only the beginning of providence smiling upon them. A couple of days later, Matt and Laura Tomley (Justin Louis and Christine Tucci) decide to adopt the siblings. The only problem with the kindly couple's offer is that Matt is terribly allergic to animals with fur, and the New York apartment where they live doesn't allow dogs. Given the circumstances, the youngsters choose not to tell their new parents about the pooch they have carefully packed in their luggage.
Once in the Big Apple, the sisters' new life consists mostly of getting acquainted with the Tomleys and keeping Chestnut's existence a secret. The first task is just a matter of trusting the abundant love the couple is trying to share. The second is a growing concern because the mutt is a Great Dane. Getting bigger and bigger with each passing day, the challenge of hiding, feeding, walking and toilet-training the horse-sized canine takes all the creative ingenuity the two posses.
The situation reaches epic proportions when the dog sniffs out a couple of thieves who have been breaking into homes in the Manhattan area. Unfortunately, his stealthy motives are misunderstood amidst the property damage and flying food that ensue.
While the plot and slapstick antics are as predictable and silly as the cute kids and puppy on the cover indicates, the sentiment in the film is still in the right place. Only a few moments of mild peril may present concerns for young viewers (especially when an animal is injured). With charming performances from the child cast and the dog, Chestnut's message of the warmth and importance of belonging is sure to paw its way into the hearts of family audiences.