The defining moment of “Ocean’s Thirteen” occurs when Danny Ocean (George Clooney) pooh-poohs a rapacious casino mogul’s threats with a hard-to-beat rejoinder. Danny doesn’t claim to be tougher, or trickier, or richer than the dark forces Willie Bank (Al Pacino) could summon at the snap of a finger. He just knows all the baddies Bank knows and, as he evenly explains, “They like me better.”

With the third installment of the celebrity heist series, Ocean’s crew has ascended to some hyper-evolved level of unruffled self-assurance. The relaxed confidence exceeds all previous incarnations — the ring-a-ding Rat Pack cool of the 1960 original, the knowing breeziness of the first remake, 2001’s “Ocean’s Eleven,” and the nerviness in the face of rug-pulling oneupmanship in 2004’s “Ocean’s Twelve.” The mind of “Ocean’s Thirteen” is as clear as the beautifully photographed azure sky above Las Vegas, like a master gambler in the zone.

This is not, however, a good thing. “Ocean’s Thirteen” locates the thin gray line between who-cares poise and total oblivion — and glides on past. It’s a sleepy, genial trifle that basically forgets the second half of “fake it ’til you make it.” For actors and filmmakers alike, all that unflappability means a heist without suspense, a charm offensive that doesn’t attack, and a con that’s forgotten its hooks.

So what happens in Vegas? For this go-round, the gang of 11 is roused to action by a grave injustice done to one of their own: Slimy Willie Bank swindles fellow old-schooler Reuben (Elliot Gould) out of a huge casino deal. Reuben suffers first-generational disillusionment (“But you shook Sinatra’s hand!” he exclaims) and then a heart attack. After gallantly giving Bank the chance to repent, the Ocean’s crew plots a payback to hit the egotistical wheeler-dealer where it hurts: break Bank’s bank at every table during the ill-begotten casino’s gala opening.

To fund the operation, they look to their old nemesis, Terry Benedict (Andy Garcia), the ruthless casino honcho from the previous movies. According to his loan shark terms, the gang must also steal Bank’s shimmering collection of diamond five-star awards. All this must occur in the plain view of a casino security system powered by artificial intelligence, deep within the spiral-towered casino-hotel.

Beating the house, like any daredevil caper, demands a masterpiece of synchronized timing. But in “Ocean’s Thirteen,” that means a lackadaisical setup that takes its sweet time well past the halfway point. Like a winning jackpot, the film messily spews forth cons upon sub-cons: intricately rigged tables and slots, naturally, but also a fake earthquake, rabblerousing in a Mexican dice factory, and the seduction of Bank’s foxy factotum (Ellen Barkin) by a faux-schnozzed Linus Caldwell (Matt Damon). And since prestige obsesses Bank, the team also torments a Zagat-style casino rater who is visiting on the big night, in an irony not lost on this critic.

If that sounds like a lot, don’t worry: “Ocean’s Thirteen” has the con artist’s habit of laying out each trick in detail, only to pull logic-defying surprises out of its sleeve. But under Steven Soderbergh’s impatient direction, the so-called caper has a flattened affect, perilously low-key, which crimps a sporadically funny script (as does some strangely murky audio during a lot of the dialogue). You’re not happy that the Ocean’s crew is getting away with their scheme, or unhappy; you just wonder when they’ll get done with it (and stop talking about it).

This is where star wattage should come in, but the big names get lost in the fine print of the heist details and a looming case of warm fuzzies about male camaraderie. Mr. Clooney and Brad Pitt (who seems a bit of a ghost in the film) spend their time guiding the ship and cryptically commiserating about relationships in the absence of prequel flames Julia Roberts and Catherine Zeta-Jones. You can sense that Mr. Soderbergh is trying to tuck little shifts in tone into still moments, but the movie is too brittle, the characters far too ephemeral.

The shift in dynamics does at least allow Mr. Damon and supporting Oceanites like Casey Affleck to jig a bit in the abandoned limelight. Carl Reiner’s oldster con man is again a sly pleasure, and Don Cheadle finds a suitably ridiculous disguise to mitigate his dead-on-arrival Cockney character. Scott Caan, Eddie Jemison, Bernie Mac, and Shaobo Qin (who once again speaks Chinese exclusively but is understood by most of his colleagues) all return to punch in for hit-and-miss bits, and Eddie Izzard floats about as the team’s go-to consultant.

“Ocean’s Twelve,” the preceding film and perhaps the best of the series, was unfairly pilloried for the campaign of tabloid coverage surrounding its release, but the artful dodging of the film itself — hopscotch plot, careening comedy, and restless visuals — is sorely missing in the latest sequel. Mr. Soderbergh, eagerly doing cinematographer duties, paints beautifully with the warm-and-cool bottle-glass hues that have obsessed him at least since his 1995 heist movie “The Underneath,” but it’s hard to imagine him — or his fellow producers — staying interested enough for yet another follow-up. For the Ocean’s crew, it’s time to cash out and go home.