With Pirates of the Caribbean: At World's End, the summer blockbuster begins to approach the level of pure abstraction. Adrift in the windless seas of its 168-minute running time, the viewer passes through confusion and boredom into a state of Buddhist passivity. Swords are crossed, swashes buckled, curses lifted only to descend again. People marry, die, come back to life, transform willy-nilly into barnacle-encrusted ghouls. There are reasons why all this is happening, reasons that might be clear if you've recently pored over the previous 294 minutes of pirate lore. Like all abstract art, At World's End is best approached non-narratively, as an experience rather than a story. Still, since that experience will cost you $10 and nearly three hours of your life, I'll try to sort through the flotsam and make sense of the thing.

As the film opens, Lord Beckett (Tom Hollander), the head of the British East India company whose crisp powdered wig is evidence enough of his villainy, announces a kind of 18^th-century version of the Patriot Act: The right of habeas corpus has been suspended, and anyone suspected of piracy—not excluding cute Dickensian urchins singing sea chanteys—has been sentenced to hang.

The only pirates not in this lineup are the ones we care about: Will Turner (Orlando Bloom), Elizabeth Swann (Keira Knightley), Capt. Barbossa (Geoffrey Rush), and the crew of the Black Pearl. They're down in Singapore, battling a Chinese pirate (Chow Yun-Fat) for the possession of a mysterious map. That procured, they sail for the Land of the Dead to rescue Jack Sparrow (Johnny Depp), who, if you'll consult your glossary, sacrificed himself to the jaws of a sea monster at the end of the last installment. But dying in the Pirates of the Caribbean world is sort of like being audited by the IRS: Sure, it's a drag, but as long as you talk to the right people and pony up the loot, it'll be over with soon enough.

The tax lawyer for the Black Pearl crew is Tia Dalma (Naomie Harris), a voodoo priestess who, it turns out, happens to be the sea goddess Calypso in human form, hence her power to revive the dead. She was once the lover of Davy Jones (Bill Nighy), captain of the Flying Dutchman, who, pursuant to some unspecified betrayal, has been cursed to wear a rubber octopus face that obscures what a good actor Bill Nighy actually is.

Oh, I almost forgot: Will Turner wants to rescue his father (Stellan Skarsgård) from a curse that's made him part of the hull of the Flying Dutchman. Skarsgård, in one short scene with Bloom, provides the film's most moving moment as the melancholy, amnesiac Bootstrap Bill. There are more subplots involving Elizabeth's father, Gov. Swann (Jonathan Pryce), her former suitor, Norrington (Jack Davenport), and the ever-shifting location of a trunk containing Davy Jones' heart, but elucidating them would make this review longer than Middlemarch. The geeky intricacy of all this plot arcana no doubt accounts for a part of the franchise's appeal. There's a scene about two-thirds of the way through in which pirate representatives of various nations meet to elect a king, that resembles the late Star Wars movies with their endless council discussions and legislative wrangling.

At World's End was shot simultaneously with the second Pirates installment, Lord of the Rings-style, but that doesn't keep either film from seeming made up as the crew went along. Still, the director, Gore Verbinski, does have a touch with big action sequences, particularly stunts involving the physics of the human body in motion: flung from catapults, coasting down zip lines, swinging from masts, and so forth. Some of the physical gags in Pirates almost recall Buster Keaton, with the important exception that Keaton was actually doing this stuff. The combination of stunt doubles and CGI enhancement that enables Verbinski's gee-whillikers battle scenes somehow drains the joy out of even the niftiest tricks—but maybe that's just me.

Even when Johnny Depp is being milked for cuteness as he is here, his Jack Sparrow remains a bizarre, antic creation: an effeminate Falstaff as played by a spray-tanned Errol Flynn. Keith Richards, whom Depp has cited as one of his original inspirations for the character, appears in a cameo as Jack's grizzled father Capt. Teague, provoking inevitable fantasies of a sequel in which Jack snorts his dad's ashes after the old pirate falls out of a coconut tree.

The final destination on that much-fought-over map—not to mention a juicy tidbit that's revealed after the interminable closing credits—both hint that a fourth film might not be out of the question, if this one rakes in doubloons the way the first two did. Apparently cursed seafarers aren't the only thing capable of coming back from the dead if the price is right.