Starting with Old Yeller and continuing with films like the less iconic Marley & Me, American cinema has a simple trick for an instant tearjerker: give us a boy-and-his-dog story, then kill the dog. A Dog's Purpose ornaments this formula with an existential theme strung across many lifetimes, all from the view of a hungry, mischievous pooch.
Finding Bailey's purpose
What is the meaning of life? Are we here for a reason? These are heavy questions, but they're the first thoughts voiced by the feral pup who will become Bailey, our main character. When his first life is cut short by animal control, he realizes just playing and eating all day hadn't added up to much, and in his next life, his determination to find his real purpose leads him into the home of Ethan, a young boy with a troubled home life.
Through Bailey's perspective, we watch Ethan's father try to improve in his career, Ethan's burgeoning football successes, and his blossoming relationship with a girl named Hannah. But because Bailey doesn't understand many human words, and is more concerned with food and playful antics, it's hard to care when the father descends into alcoholism and abuse, Ethan loses his dreams of pro football when a housefire incident fractures his leg, and he pushes Hannah away in bitterness.
Bailey only seems to somber up when Ethan goes off to college and Bailey dies of loneliness—sorry, I meant kidney failure—and his "boy" rushes to his side just in time to say goodbye.