Evie is overjoyed when she is given her very own puppy, Leo. Leo adores Evie - he loves to be cuddled, sleeps on her bed, and welcomes her home from school every day with a wag of his tail. But it's not long before another new member of the family arrives: Evie's baby brother, Sam. Suddenly, no one has time to take care of Leo, let alone play with him and take him for walks. Soon he finds himself unwanted and all alone.