Imagine a cross between “Charade” and “Mission Impossible” that mimics the over-the-top action of the latter but, sadly, has little of the charm of the former and you’ll have some idea of what “Knight and Day” is like. Like Stanley Donen’s film, it aims for a Hitchcockian feel, but unlike that romp, utterly fails to achieve it, smothering any hope of success in mindless mayhem, much of it of the CGI variety.

The Cary Grant stand-in here is Tom Cruise—not a fair trade. He plays Roy Miller, a smiling stranger who literally bumps into June Havens (Cameron Diaz)—a classic car restorer!—in the Wichita airport while both await a flight to Boston. She’s almost bumped a second time—from the flight—but is let on at the last minute, thanks to the intervention of some mysterious men watching the two, only to find that the plane’s nearly empty.

The reason becomes apparent in short order. While she’s in the lavatory, everyone else on the flight—including the pilot—tries to kill Roy, who dispatches them all in the first of the innumerable action sequences. He then lands the plane in a field and after warning the befuddled June not to trust the men who will soon show up to question her, deposits her at home.

Of course, those black-suit types soon show up, led by Fitzgerald (Peter Sarsgaard), who identifies himself as an FBI agent in pursuit of Miller, who’s described as having gone rogue. As June’s being whisked off to “someplace safe” by them, Miller reappears to blast most of the suits away and free June from their clutches, telling her that Fitzgerald’s really the bad guy.

Thus begins a long chase in which Roy and June are pursued across the globe by Fitzgerald, his boss (Viola Davis) and their agency associates, as well as by a sleazy international arms dealer (Jordi Molla). There are lots of fights, chases on foot and in cars, gun battles and even a running-of-the-bulls segment in Sevilla (Pamplona presumably being overexposed in that regard). One sequence, in which our heroes are pursued across a Pacific island by a plane, is even obviously designed as a homage to the iconic crop-dusting scene in “North by Northwest,” but is clumsily edited and has nowhere near an equivalent punch. One of the movie’s tricks is to skip over difficult transitions by having one of the principals drugged and showing things from that perspective; when they black out, what happens can just be omitted and left to the viewer’s imagination. It’s a pretty cheap device in every respect, but one accepts it as a means of keeping the picture from being even longer than it is.

The MacGuffin, as Hitch would have called it, consists of an inexhaustible power supply and its shaggy young inventor (Paul Dano), both of whom Roy claims to be protecting from the dastardly Fitzgerald. But the question for June is whether Miller’s who he says he is, or he’s the one trying to sell the thingamajig to the bad guys. In other words, June is confronted by the same issue as Audrey Hepburn in “Charade”—whom do you trust? The matter is complicated, as it was in Donen’s film, by the fact that she’s obviously falling for her charming companion.

All of which might have worked had Patrick O’Neill’s script been cleverer, James Mangold’s direction less emphatic, and John Powell’s score more imaginative. It must be said, though, that the movie looks opulent. Production designer Andrew Menzies and the art directing team supervised by Greg Berry have done spiffy work, and Phedon Papamichael’s widescreen cinematography takes advantage of the locations and their work.

Unfortunately, the leads come up short. Cruise, helped by lots of effects, excels in the physical stuff, but he’s not nearly as charming as he thinks, though he tries to convince us he is by flashing those pearly whites as often as possible. Diaz is hampered for the most part by having to play June as the same sort of hapless ditz that Katherine Heigl had to pretend to be in another recent chase romance, “Killers.” She gets to show some smarts in the final reel, but by then it’s not enough. Sarsgaard, meanwhile, is wasted in the Walter Matthau “Charade” role, and Davis fares even worse, while the always interesting Dano makes the most of his few moments as the geeky inventor. Marc Blucas has fun with his early scenes as June’s gung-ho fireman ex-boyfriend, and Celia Weston and Dale Dye have some with theirs as a long-married couple at the close, but Maggie Grace Rodney is totally anonymous as June’s sister. The less said about Molla’s oily villain, the better.

It would be nice if Hollywood would provide us with one sophisticated piece of adult entertainment this summer. But to misquote Cole Porter, “Knight and Day” isn’t the one.