Frank (2007)

A young urban family spends summers on an idyllic island. When an abandoned, mangy mutt wanders onto the property, the dad alerts Animal Control - but the children beg to keep the dog. A compromise is reached: the kids can nurse FRANK back to health, but must put him up for adoption when summer is over. As he regains his strength, Frank risks his life to bring the family together in ways no one imagined...