Engaging critically with Dog Movies can be a challenge for a critic. Who wants to be the crank who scoffs that the heartwarming animal movie is just too contrived and sentimental? But it can be hard to avoid, with the sickly sweet pandering pabulum of recent films like “A Dog’s Purpose” and “Dog Days.” Fortunately, “A Dog’s Journey,” the third in a trilogy of films adapted from W. Bruce Cameron’s novels, offers up an interesting, complex story into which we can sink our teeth. It has the emotional bite to match its somewhat hokey bark.

Both “A Dog’s Purpose” and “A Dog’s Journey” are metaphysical and philosophical films that purport the theory that the same dog spirit has been reincarnated again and again into different canine forms over its owner’s lifetime, always trying to make it back home. It’s a fantastical idea, and all rather Buddhist for a film that traffics in heartland family values nostalgia cheerleading. But it’s a fantasy that dog lovers want to believe. Wouldn’t it be nice to think our dogs get reincarnated into our next furry friends?

Bailey, the St. Bernard from “A Dog’s Purpose,” reappears as a kindly older dog in “Journey,” the beloved pet of Ethan (Dennis Quaid) and Hannah (Marg Helgenberger). Bailey bonds with Ethan and Hannah’s toddler granddaughter, CJ (Emma Volk), while their daughter-in-law Gloria (Betty Gilpin) grieves the death of CJ’s father in a car wreck. A selfish and vain woman, she impulsively leaves the family farm with her daughter, denying the grandparents any chance of seeing her again while tossing off vague accusations about CJ’s father’s life insurance policy.

Losing a beloved dog is a part of pet ownership, and as Ethan says goodbye to his friend Bailey for the final time, he implores the dog to find and protect CJ in his next lives, because she’ll need it. CJ grows up a lonely, sad girl (Abby Ryder Fortson and Kathryn Prescott), but Bailey finds her again and again, as a beagle named Molly, a mastiff named Big Dog and finally, a Yorkie named Max, who has the greatest influence on CJ’s life, and helps her to believe in the magic of the animal’s spirit.

It’s about halfway through the film when one realizes how much deeper director Gail Mancuso is going with this dog’s journey. This isn’t all romps in the tall grass and stories of puppy heroism or feats of strength — it’s about family trauma, death, domestic abuse, neglectful parenting, addiction and life-threatening illness. It’s about how dogs can fill the hole in your heart that a person might leave.

The whole shtick of these movies is the doggy voice-over, performed by Josh Gad, and it lightens the film. But going dark and emotional makes the film work better than the prior two. Because even among all the coincidences and twists of fate Molly and Max enact, what hits home the most is dogs can offer people unconditional love when they need it most, and that has always been a dog’s purpose.