Though abandoned as a puppy, Happy is now in excellent health under the care of Miku's family. He plays with the child, goes for walks with the enthusiastic Father, and eats delicious meals prepared by Mother. Consequently, there is no doubt that he is enjoying life to the fullest. Unfortunately, when Father develops a chronic illness, the strong family bonds in the home gradually weaken. Bit by bit, the family becomes more fragmented—until only Happy and Father remain. Unable to support himself in his condition, Father sets a single goal for himself and his dog: to travel to the far south. Their journey may have its ups and downs, but Happy will always remain man's best friend.