Twins Samuel and Lucy long for a puppy - and this year's Christmas is set to be the best ever, as they are taken to Battersea Dogs & Cats Home and meet Snowy, the little Saint Bernard! 

One day, Samuel and Snowy go off exploring, leaving Lucy behind. Feeling left out, she takes Snowy on a late-night adventure, but a blizzard sets in and Lucy is soon lost in the dark. Can Snowy lead her home to safety?