Any film starring a dog and airing for holiday-season consumption raises certain expectations—the right word is probably suspicions. All are borne out in the new, mercilessly affecting Hallmark Hall of Fame production (Sunday, 9-10:30 p.m EST on CBS) titled “A Dog Named Christmas.” (The film is based on the novel of the same name by Greg Kincaid.) The plot is a gut-wrencher, though not lethally so; its hero a creature of many parts, most of them flawless. Christmas endures tribulations and trials whose outcome is never in doubt: Nothing seriously bad is going to happen to a dog named Christmas, or any other kind, in a film like this—or to his supporting cast of humans, the good people who have taken him in.

That not-so-subliminal understanding—call it a willing suspension of disbelief in the obvious—won’t, of course, block those freshets of anxious suspense loosed over every second of a drama focused on the fate of a dog who has found a home in which he may or may not be allowed to stay. The capacity to sustain anxiety and a palpitating apprehension about the trials confronting the characters is a signature skill of Hallmark productions—and given their famously optimistic nature, it’s no small feat.

This film is no exception, though the chief protagonist himself manages to elude all sense of apprehension. Blissful, in a home to die for, Christmas, doglike, has no idea of endings; unlike the humans around him he’s innocent of grim possibilities. He’s come to his happy home on a Kansas farm because the McCray family’s 20-year-old son, Todd (Noel Fisher), has heard that the local shelter is looking for families to take dogs home for the Christmas holiday. The idea—to give them some respite from their cages and, with any luck, entice their hosts to give them a permanent home. The developmentally challenged Todd, devoted to animals, has his heart set on the project—on a dog, that is: the one presence his otherwise understanding father, George (Bruce Greenwood), has always banned from the household.

Still, with the help of his mother, Mary Ann (Linda Emond), Todd prevails—on the strict condition, laid down by his father, that the dog named Christmas be returned to the shelter the day after the holiday. Thereby hangs the bare-bones plot of a far more complicated story of pain and remembrance. Todd’s father is a Vietnam War veteran, scarred by shrapnel, who found love and a sustaining marriage with Mary Ann—a role of startling power in Ms. Emond’s eloquent portrayal. Middle aged and maternal, but still with a glow about her, she’s the family force of reason, affection and, for a second or two, pure fury—at George’s intransigent rationalizing about his attitudes regarding the dog. She knows the reasons go deeper than he’ll allow, and so, soon enough, do we.

Those reasons don’t come as any great surprise, nor are they meant to, nor do they quite add up psychologically. One of the great mysteries in life are those countless people one meets, ready to hold forth, with fervor, on their great love of dogs and on their wish that they could have one. Alas, this is a pleasure they cannot allow themselves, they explain, because they once had a dog 15 years earlier. And the dog died. And they can’t risk such loss again. That is essentially the theme sounded in George’s attitudes, and—though the explanations for his are at least grounded in the extreme experience of war and loss—they, too, have the ring of falsity.

None of that detracts from the impact of this enchanting film, or from the sterling performances of Messrs. Greenwood and Fisher. Not to mention that of the 10-year-old yellow Lab, Johnny, a hero incapable of a false note, here in his first starring role.

Originally Published by the Wall Street Journal