Owd Bob.

Recently orphaned David must move to the Isle of Man to live with his grandfather, Adam, who's a sheep farmer. Both long for the end of the summer, having nothing in common but their love for dogs, notably Adam's precious champion sheepdog Bob. David strikes a friendship with Maggie, the sassy daughter of friendly neighbor Keith Moore, but Adam hates that family on account of an old canine competition-related tragedy. Other neighbors suspect Bob and the Moore's dog of the recent series of nocturnal sheep-kills.