The exploits of the title sheepdog provide the basis of this family-oriented comedy fantasy. Digby started out as an ordinary puppy but then one day got in to a bowl full of Project X, a special formula meant to grow larger vegetables. As he galumphs along in the countryside causing all kinds of trouble, the Army decides to blow the big woofer to kingdom come. Fortunately for Digby, his devoted owner is frantically searching for the serum that will save him.
~ Sandra Brennan, All Movie Guide