Is it possible to do people good by doing them harm? Plato didn’t think so; the director David Frankel and the screenwriter Allan Loeb do. In their fascinatingly bad fantasy “Collateral Beauty,” which opens today, the evil they depict is one that’s of the moment, and that weaves itself into the very fabric of the story they tell: gaslighting. Which is to say that it’s a story set in the world of the great universal gaslighting: advertising.

I confess: I worked in advertising for a few years, in the nineteen-eighties, and it was so much fun that I had to leave; otherwise, I’d have stayed. I retain a fondness for my experience, for people in the field, and for movies on the subject. (The classic cinematic text remains the inspired rant delivered by Kirk Douglas in Joseph Mankiewicz’s “A Letter to Three Wives.”) That’s why the first scene of “Collateral Beauty” raised hopes high: it’s a staff meeting at a small agency of about forty people, who hear an inspiring address by one of its principals, Howard (Will Smith), about the noble cause that advertising serves. In lofty rhetorical flow, Howard explains that advertising isn’t about selling things—it’s about addressing people’s deepest desires and motives (his phrase: “What is your ‘why’?”). Then he raises the bar higher, asserting that advertising is about confronting the three basic centers of human concern—love, time, and death: “We long for love, we wish we had more time, and we fear death.”

I was already won over; Smith’s performance, even as he delivers that boldly crafted line of bullshit, has a sentimental vigor and a tremulous sense of nuance, highlighted in closeup, that reminded me from the start why he’s one of the generation’s exemplary stars. Yet, though his performance in “Collateral Beauty” never lets up, and ramps up the emotional voltage, it does so in the cause of a plot that is so absurd that it’s both a tall-tale joy and a cringe-inducing pain even to relate. It’s another entry in that overdone genre, the dead-child movie (see also “Arrival”); flash forward three years to Howard, now seemingly catatonic in motion, busily filling the agency’s big conference room with a massive architectural array of colorful dominoes, which he then sends spilling sequentially to the floor.

Howard has been rendered nonfunctional by the death of his six-year-old daughter, two years earlier, and his three business partners, Whit (Edward Norton), Claire (Kate Winslet), and Simon (Michael Peña), see the agency spinning out of control without Howard’s engaged stewardship. Clients who depend upon his insight are threatening to take their business elsewhere; a lucrative buyout offer from a big (real-life) agency conglomerate, Omnicom, is at risk of expiring because Howard, the majority shareholder, won’t even look at the paperwork. Then a Rube Goldberg-esque series of coincidences intervenes: Whit, impressed by an actress named Amy (Keira Knightley) at a casting session, follows her out the door and tracks her down to a small theatre, where she’s rehearsing a high-arty lyrical work with two colleagues, Brigitte (Helen Mirren) and Raffi (Jacob Latimore). He learns that they need money to stage their production, and he gets an angelically diabolical idea—he offers them the money, with a condition.

One idiosyncrasy of Howard’s ritual of grief is his letter-writing; he’s the Herzog of mourners, writing missives of aggressive complaint to his three guiding abstractions, Love, Time, and Death. Whit’s idea is to get hold of the letters and to hire Amy, Brigitte, and Raffi to portray the three abstractions and to answer Howard’s letters in person. The three actors will stalk Howard and infiltrate his life. Meanwhile, Whit (unbeknownst to the actors) hires a private eye (Ann Dowd) to follow Howard and observe his behavior while he interacts with the three characters, so that Whit, Claire, and Simon can get Howard declared incompetent—and so that they can sell the agency to Omnicom without his involvement. Howard’s three closest colleagues and best friends are, in other words, gaslighting him, seriously but with good intentions: they do hope that the psychodramatic exercise of placing him in the physical presence of cosmic forces will prove therapeutic, and when the buyout takes place it will make him (as well as them) very rich.

Frankel’s movie brings together two extraordinary realms of activity—advertising and theatre—and reduces them to mere incidentals of its gaslighting plot and its maudlin dive into recovery from grief. (For that matter, the plot’s tenuous implausibilities call into question the very possibility of recovery; its realm of fantasy seems to strain after secular miracles.) The failure of “Collateral Beauty” is all the more grievous for the waste of its superb actors. The cast works hard to invest the dramatic frippery with an air of lived experience and grounded emotion, but the grotesquely oversimplifying script, which assigns each character a big problem (and gives Whit many big problems) to overcome, doesn’t help. Naomie Harris, as another bereaved parent whom Howard encounters in a support group, also exerts herself heroically in an underwritten and underconceived role. What’s more, the movie’s unquestioned panoply of sumptuous creature comforts and its blithely oblivious, even offensively wary view of less conspicuously prosperous New York neighborhoods suggest filmmakers who rarely set foot off Park Avenue. That, too, is a form of gaslighting.

Oddly enough, “Collateral Beauty” isn’t the only gaslighting movie of the season, but it’s the only one that’s spoiler-proof—the story is more or less all in the trailer, and it’s already as exasperatingly diffuse and leadenly artificial in the trailer as it is in the movie. By contrast, the science-fiction drama “Passengers,” opening next Wednesday, is a story of gaslighting in space, but, unlike “Collateral Beauty,” the trailer gives nothing away, and any reviewer who has the gall to do so will deprive readers of any reason to see the movie. “Passengers” is a feature film that plays like an inflated “Twilight Zone” episode, a one-trick pony that sets up its spring-loaded mechanism like the catapult for a ready-made barrage of think pieces that will have to dance around the specifics while zeroing in on matters of morality.

“Passengers” is set far in the future, when humans are offered the chance to leave the overcrowded Earth and colonize a distant planet. The trip, by autopiloted spaceship, takes a hundred and twenty years; the travellers and the crew are put into suspended animation in individual pods and are to be awakened just before arrival. But, after an unforeseen calamity thirty years into the voyage, two passengers, Aurora (Jennifer Lawrence), a writer, and Jim (Chris Pratt), a mechanical engineer, are prematurely reanimated and thus forced to live together for the rest of their lives as the only two waking humans aboard an essentially uninhabited—and enormous—spacecraft. (Actually, there’s also a bartender named Arthur—played by Michael Sheen—onboard, but he’s an android.)

The passing joy of “Passengers,” as directed by Morten Tyldum, isn’t at all in the ineffable story but in the drolly conceived quasi-documentary details of space travel—the mechanized and economically stratified delivery of breakfast foods, the chrome-plated robot waitstaff with their French accents, the holographic greeters, the swimming pool with a cosmic view. Despite the embedded dramatic twist of who-did-what-to-whom, the movie’s most memorable drama is utterly impersonal—the effect of gravity loss on people in motion. But over all the drama of “Passengers”—about the collateral benefits of hurtful actions, about forgiveness, about the difference between achieving immortality in one’s work and achieving it by not dying—is less important and less memorable than its occasionally engaging sci-fi wonders. The material reality of a domain of pure fantasy comes intermittently to life in “Passengers” in a way that the material reality of the contemporary world never does in “Collateral Beauty.”

Fantasy, even when it’s rooted in practical details and doesn’t involve any metaphysical impossibilities, is the hardest genre to pull off, for the simple reason that life is interesting. A drama or a comedy that sticks close to experience has the intrinsic virtue of documentary—and, as with documentary itself, less is usually more. Modestly naturalistic dramas and comedies may, in their ordinary incarnations, fall short of the heights of cinematic achievement by lack of imagination and symbolic extravagance, but they also often offer an element of reportorial observation that surpasses, in breadth and depth, the filmmakers’ limited inspirations. Fantasy, which is by definition extraordinary, requires an extraordinary sensibility to realize it with any sense of substance. It requires a sense of style as well as a sense of metaphor, a sense of abstraction, of the conjuring of life and the realization of solid ground through perfectly chosen touches. That’s why, when fantasies succeed, they do so mightily—for instance, “The Future,” “Chi-Raq,” “The Grand Budapest Hotel,” “Holy Motors,” and “Gentlemen Broncos.” When they fail, they’re almost completely empty and offer hardly anything at all worth watching—despite any collateral beauty.