As a tribute to his parents by a loving son—as producer Jonathan Cavendish describes it in one of the film’s closing caption cards—“Breathe” certainly succeeds. As a drama, on the other hands, it’s a sappy tearjerker, so shameless in its employment of manipulative clichés that at times it seems almost a parody of the genre. That may be a bit surprising, since it comes from the pen of William Nicholson, who, in “Shadowlands,” managed to elevate what was basically soapoperatic material to a higher level. Here, he fails utterly to do so. And actor Andy Serkis, in his first directing assignment, accentuates the script’s mawkish elements rather than underplaying them, sabotaging a good cast in the process.

Andrew Garfield, in what is certainly his weakest performance to date, stars as Robin Cavendish, a young, energetic Brit, an ex-military man struck down by polio in 1958 at age 28. The preceding year he had married Diana Blacker (Claire Foy), who—at least in this telling—he met “cute” during a cricket match. After the couple returned to Kenya, where he had a job as a tea broker, and danced to Bing Crosby’s recording of “True Love” (intended, obviously, as shorthand for their honeymoon), he suddenly fell ill. Paralyzed from the neck down and unable to breathe without a respirator, he was returned to England with his now-pregnant wife.

There Robin is effectively warehoused, along with other similarly afflicted patients, in a hospital run by stern Dr. Entwistle (played by the appropriately named Jonathan Hyde), where he becomes so depressed that he yearns to die. Diana reacts by demanding to take him home, which she eventually does against Entwistle’s orders. But the restriction of being tied to his bed and the respirator alongside it still takes its toll, and so Robin’s friend, Oxford don Teddy Hall (Hugh Bonneville), who happens to be an amateur inventor, devises a wheelchair with a built-in respirator that allows a degree of mobility, even if the Cavendishes take things a bit far by going on a jaunt to Spain, where disaster nearly strikes. Eventually, however, the device is brought to the attention of Dr. Aitken (Stephen Mangan), head of a commission on treatment of the disabled, who champions it in the field.

This is clearly an inspiring story, and if played with even a modicum of subtlety it might have been a truly affecting film. Unfortunately, it is not. Nicholson’s dialogue is so on-the-nose that it’s often unintentionally funny, and Serkis’ sledgehammer direction lets no big moment pass by without italicizing it. (The same can be said of Robert Richardson’s cinematography, which bathes the widescreen images in a heavenly glow, and Nitin Sawhney’s syrupy score, which goes completely bonkers when it inserts the triumphal march from “Aida” at a couple of points.)

Garfield suffers most from the heavy-handedness. The role is not an especially inviting one in any event—it’s pretty much a less showy version of the one for which Eddie Redmayne won his Oscar playing Stephen Hawking—but all Garfield is given the opportunity to do for much of the footage is smile so broadly that the effect is more like rictus. And while Foy exudes concern and spunk, she offers nothing special either. Even Bonneville, decked out in an unflattering wig, is sadly anonymous. (The aging makeup overall is not great.)

The only member of the supporting cast people will notice—apart from the grim Mr. Hyde—is Tom Hollander, who does double duty as Diana’s twin brothers. The effects team have done a splendid job of making it possible for the two Hollanders to appear together in individual scenes and interact with each other, but the trick seems more a tech reel for The Imaginarium, the digital outfit that Cavendish and Serkis run jointly, than a dramatic necessity—though Hollander is undeniably engaging.

Curiously, though “Breathe” is a celebration of life that might well be applauded on that ground, it has a couple of aspects that could give its proponents some pause. One is Robin’s atheism, which is indicated in several instances—most clearly in his encounters with pious clergymen. The other comes at the close, when what amounts to an approval of euthanasia might be quite troubling to some viewers inclined to support the film in terms of its broader message.

One has to commend the makers for touching on such matters. A pity that they didn’t show more imagination in freeing themselves from formula in telling the larger story.