The Invisible Leash

When Zack loses his dog Jojo due to old age, Zack feels a rang of emotions from sorry, to grief and anger, Zack's parents try to explain to him that even though Jojo is gone Zack still has a leash that connects Zack and Jojo's heart to each other, while taking a walk Zack realizes that this leash must be real because when he thinks of Jojo he feel a tug at his heart.