Leave it to Michael Bay, the director of such nuanced motion pictures as Armageddon and Bad Boys, to take an unsettlingly plausible premise about cloning, spruce it up to look both sleek and serious, and then nearly blast it to smithereens with massive chases and explosions. 

"Nearly", because The Island is a cool movie -- part perfume commercial, part sci-fi thriller, and part roller coaster ride -- and enough substance is able to survive Bay and the three credited screenwriters' more numbingly nuclear choices.

Clones are people too, or close enough. If that wasn't what many believe or suspect, there wouldn't be much of an ethical debate surrounding scientific research in the field. And if we didn't think there was something morally dodgy about playing God with genetic material, the concept driving this film wouldn't be so chilling, even though sci-fi aficionados and movie-of-the-week addicts might not find it especially original. In fact, during the first reel you're meant to have Brave New World and other well-known dystopian books and films in mind.

Ewan McGregor and Scarlett Johansson play Lincoln Six Echo and Jordan Two Delta, handsome residents of what appears to be a sterile, mid-21st-century spa. Two survivors of an apocalyptic event involving carcinogens, they bide their time with a couple thousand others getting extremely fit until they win a lottery and are transferred to an idyllic tropical locale where they will live free and reproduce, ensuring the survivor of mankind. LCD monitors display readings from gauges that detect the tiniest changes in bodily systems, and their diets are restricted by grouchy staff people and their general behavior by unfriendly guards. They dutifully adhere to the three Ps: be polite, pleasant, and peaceful; and proximity rules prevent certain forms of fraternization. 

Bay executes the first third of the movie with such in-your-face panache you know you're being led down the garden path. Obvious product placements also tip you off -- all is not what it seems. The truth turns out to be genuinely frightening, as the gruesome fate of one resident (Michael Clarke Duncan) shows.  Lincoln has nightmares and starts asking questions of a techie staffer (Steve Buscemi) he's befriended. The facility's overseer, Dr. Merrick (Sean Bean), is concerned enough to run a synaptic brain scan using little bugs that enter Lincoln's brain through his right eye socket. When he and Jordan eventually go AWOL, Merrick calls in a commando (Djimon Hounsou) to track them down. The chase is on.

To explain more would spoil the movie. The polished, arresting images that keep you intrigued during the first reel give way to jolts of sensory overload that are absorbing in their own right. By design, the audience is led from a science-fiction cocoon into the overblown world Hollywood specializes in wowing audiences with -- often, as here, by creating and then blowing up.

McGregor and Johansson convey the innocent, child-like dimension of their characters (although once on the outside, Lincoln and Jordan get awfully smart awfully quickly) and while lovely specimens, aren't robotically attractive. McGregor shines not during the chases, driving motorcycle-airplane hybrids, but when his character comes face to face with his doppelganger.

Overblown elements notwithstanding, neither side of The Island is so far-fetched. As the spectacle unspools, the vision gets more and less horrific. If ever a movie shouldn't have a positive outcome, it's this one. But we're taken on an entertaining ride, a steady progression toward reality as Hollywood action directors understand it -- gunplay, chases, fiery explosions, and happy endings. 

(Released by Warner Bros and DreamWorks; rated "PG-13" for intense sequences of violence and action, some sexuality and language.)