The conscientious efforts of the actor Ryan Reynolds are frequently lost in movies with vaguely passé titles and short shelf lives: “Smokin’ Aces,” “Just Friends,” and, this February, “Definitely, Maybe.” But if such covertly entertaining Hollywood fare has been unfairly overlooked, “Chaos Theory,” Mr. Reynolds’s newest, is as forgettable as it sounds, a charmless and tedious comedy hidden behind the title of a straight-to-video thriller.

So back to Mr. Reynolds for a moment: His specialty, or at least the shtick I like most, is a contained mania that frays into vulnerability. In “Just Friends” and portions of “Chaos Theory,” there is an amusing and affecting disconnect between an under-his-breath motormouth and the thought bubble above him — a kind of self-observed panic, hunching his action-jock bulk. The flip side to the mood is a frantic impatience, often absurd and ultimately deflated in a scene of terrible realization.

“Chaos Theory” does not offer much opportunity for comedy, affecting or otherwise, as it yanks the actor through belabored reversals and shopworn lessons. Mr. Reynolds plays Frank Allen, a time-management expert whose life turns upside down when his wife, Susan (Emily Mortimer), playfully sets the clock 10 minutes off. The unpredictable is unleashed: He misses a ferry to his own efficiency lecture, finds himself in a compromising situation at the hotel, and, later, drives a pregnant stranger to the hospital.

Upon learning all of this, Frank’s wife naturally concludes that her husband is having a serious affair that has resulted in a baby. He instantly lands deep in the doghouse, despite an apparently stable marriage that has already produced a healthy, too-clever movie child. This is par for the course in the plot: In a goofy-sounding but sincerely played flashback, a party-giddy Susan chooses Frank from among her friends because she likes his nickname for his penis the most. (The movie as a whole is framed as an older, wiser Frank’s rueful warning to his future son-in-law on his wedding day.)

When Frank learns that his wife may in fact be the unfaithful one, a vaguely “American Beauty” fantasy of independence ensues (minus the lust for a daughter’s friend). A wretched Frank resolves to reverse his preset ways and adopt a life of whim. This includes riding a motorcycle without a helmet, chain-smoking, and following uninhibited to-do cards at random. Director Marcos Siega and screenwriter Daniel Taplitz (and probably the producers) never quite commit to “Chaos Theory” as black comedy, existential farce, or desperate tale of male woe. This leaves the audience to take it as another witless, unsatisfying romantic comedy, complete with a caddish third party in the form of the couple’s roguish college friend, Buddy (a terrible Stuart Townsend). The editing bounces us monotonously between miserably liberated Frank and glacially clued-in Susan.

Unable to wrestle free from the script, Mr. Reynolds’s style imprints itself as overworked early on, sabotaging his later, more subdued portrayal of Frank’s decline. Ms. Mortimer barely drums up the energy of someone either condemning or forgiving. Some scenes are unceremoniously goosed along by CD soundtrack-ready song selections; others are barely written, in ways that feel tacked on later (such as Buddy’s literal declaration of a need for intimacy).

But why conduct an autopsy on a movie that, despite fitting into a 90-minute slot on Frank’s planner with room to spare, drags with the barren-feeling boredom of a much longer movie? It’s hard to know exactly what clichés are intended as the upshot of the story for the young groom in the framing device who’s about to marry Frank’s daughter, but one take-away bit of advice seems clear: Do not make movies like this.