Summer blockbuster season officially starts tonight with the opening of "Mission: Impossible III," a glossy, high-octane action thriller that asks the question on everyone's lips: Can Tom Cruise - oops, we mean undercover agent Ethan Hunt - pursue a high-stakes career and enjoy a normal family life at the same time?


The answer is murky, because as the movie (and Cruise's world-tour promotion of it following his daughter's birth) shows, the job usually comes first.


The movie opens with a grand slam that echoes director J.J. Abrams' work as creator of TV's "Alias" and "Lost." It's a heart-pounding countdown to doom, with Ethan in the "Marathon Man"-like hot seat, sweating out an interrogation. He has until the count of 10 before his new bride (Michelle Monaghan), bound and gagged in the chair opposite, is toast.


The gleeful toastmaster in this instance is played in excellent villain mode by Oscar winner Philip Seymour Hoffman, whose fleshy insolence complements Cruise's hard-bodied, full-boiling sense of determination.


After this appetite-whetter and the heart-pumping theme music by Lalo Schifrin, the movie backtracks to provide the setup: Ethan is barely able to enjoy his engagement party before being called back into the field by a fellow government operative (Billy Crudup, with weird hair). He tells his sweet, clueless honey that he's off on a business trip; as in "True Lies," she thinks her guy has a boring desk job.


"Trust me," pleads Ethan, and the poor girl does.


In the third installment of the franchise based on the gadget-heavy TV show, Ethan's mission, should he choose to accept it, is to save the planet from a super-duper arms deal that's going down amid so many jaw-dropping stunts that when he gets out the defibrillator, you hope it's for you, not the comely agent about to expire in his arms.


The supporting cast, including Ving Rhames, Laurence Fishburne and gorgeous Maggie Q, is underused, but the movie delivers the goods. At least we know now why Cruise was jumping on Oprah's couch - "M:i:III" calls upon him for frequent, Olympian bursts of aerobic activity. Mostly, he runs - although he does do some quick calculus equations while catching his breath.


The plot makes no sense, and the emotional pull of Ethan's relationship is negligible. But logic and humanity would probably gum up the (fire)works. The "Mission: Impossible" template is about being resourceful, using gadgets in interesting ways to infiltrate the Vatican or swing Tarzan-like over the rooftops of Shanghai. The pangs of love can't give these guys - or their target audience - the same adrenaline rush.