It's odd that a film completely driven by movie stars is being advertised with a poster that features blank white silhouettes where those movie stars should be. Tom Cruise and Cameron Diaz are the stars in this case, bringing nothing but a generic all-purpose movie star quality to the proceedings in Knight and Day. Maybe that poster is just a tip-off -- a visual reminder that Knight and Day is a cookie cutter action-comedy, and that anyone with the right amount of box office pull could fill these blank roles.

Diaz is June Havens, Romantic Interest. There's no characterization for Havens other than being beautiful and a little clumsy ("clumsy" being the most popular studio shorthand for making her relatable to women everywhere). She twice bumps into Roy Miller, played by Cruise (also a non-character, Super Spy), while boarding a plane, and ends up having a lengthy conversation with herself in the plane's bathroom mirror over whether or not she should make out with him (because, hey, he's Tom Cruise). While this is going on, Miller is killing everyone on the plane with Ethan Hunt-style lethal precision. It's a nice intercutting of sweet and sour, and possibly the last time the movie feels legitimately dangerous.

Soon, Havens is being targeted by government operatives who are chasing rogue agent Miller, and Miller keeps swooping in at the eleventh hour, drugging Havens (in what feels like an unintentional running gag), and moving her along to the next big international location so that something can explode. They careen through explosion after explosion, bullets hitting every single object around them but them, all in the name of saving a battery prototype called Zephyr from falling into the wrong hands (the wrong hands belonging to a directionless Peter Sarsgaard).

The film could stand to be more dangerous. Knight and Day many times makes G.I. Joe: The Rise of Cobra look like United 93. Diaz stands in a hail of machine gun fire, squealing, for what feels like twenty seconds, and trots away unscathed. A bullet directly to the head through Cruise's driver's side windshield just evaporates upon shattering the glass. Cars flip over cars with such ease and regularity, you'd suspect they're made out of nothing but tin foil and gasoline. Even in the Bond flicks, Bond can get hurt. In Knight and Day, we're watching a cartoon version of what somebody thinks an action movie looks like.

Cruise has rarely been as unambitious as he is here. His hair is in place, his Ray-Bans are on, and he can smile. It's probably the same look he wore to the bank to deposit his Knight and Day paycheck. My suspicion is that he's still in career reconstruction mode, hoping that by falling back on his own brand of effortless charm, audiences will love him all over again. It's a good idea, but the wrong project to carry out that mission. Knight and Day at its best is inoffensively cute, but so disposable it's impossible to see anyone mustering any strong feelings of love for it.

That forgettable plastic quality of Knight and Day unfortunately means it's a perfect fit for this summer's line-up of disappointing wannabe blockbusters. It's a calculated, artificial formula for box office success barely disguised as a story. It's got huge stars, exotic locales, a smidgen of romance, and something blows up every fifteen minutes. That's the kind of thing that will keep you diverted enough while the lights are low, but the minute the credits roll you'll be thinking more about why the movie is called Knight and Day (the Knight part is clumsily explained; the Day part isn't) than about the movie itself. A more fun activity than watching Knight and Day might be drawing your own favorite stars into the empty shapes on the poster. Clooney and Aniston, perhaps? Pitt and Hudson? Anybody, really. The movie would be exactly the same.