The movie in question is noticeably more ambitious than one might expect from a film based not on a novel or short story, but an actual amusement park water ride. Director Gore Verbinski (2002's "The Ring") injects his multifaceted story with a steady, assured build-up and indelible technical craft. The alternately foreboding atmosphere and beauteous scenery, aided by fog-drenched watery surroundings, massive rock caverns, and deeply blue-hued moonlit nights, is extraordinary to look. Verbinski and cinematographer Dariusz Wolski (2002's "Bad Company") impress by holding an actual cinematic vision, and not stopping until they have achieved it shot-for-shot. It also helps that, with a steady amount of violence, swordplay, darkness, and potentially frightening images, the PG-13 film (Walt Disney Pictures' first ever) is not sugarcoated, dumbed-down, or aimed solely at children.

The bad news about "Pirates of the Caribbean: The Curse of the Black Pearl" is that after a stunningly involved and richly moody opening 45 minutes that had me preparing to give away the award for this year's "Best Summer Movie," the proceedings quickly went downhill. Suddenly, the freshness of the first-third was replaced by too many banally uninteresting scenes of needless exposition and an even larger amount of repetitious action sequences that basically repeated themselves over and over, ad nauseum.

Set in the 18th-century Caribbean, Captain Jack Sparrow (Johnny Depp) is a lowly vagabond sailor--bumbling but talented--who manages to save the life of lovely, headstrong Elizabeth Swann (Keira Knightley) before getting arrested for piracy. When an infamous group of immortal, undead pirates who turn to skeletons in the moonlight, led by Barbossa (Geoffrey Rush), arrive to possess a sacred gold coin owned by Elizabeth, and consequently kidnap her, courageous blacksmith Will Turner (Orlando Bloom) decides to break Jack Sparrow out of jail so they can join forces and save her. What they do not yet know is that Barbossa's master plan is a human blood sacrifice that will break their curse and restore mortality to the crew of the Black Pearl.

At nearly two-and-a-half hours, "Pirates of the Caribbean" hasn't the faintest idea how to move its plot along or wrap things up in a reasonable time frame. The climax, which should have been a grandly realized, edge-of-your-seat action sequence between the mortal heroes and skeletal villains, is nothing if not a dreary, seemingly unending endurance test that jumps back and forth between the Black Pearl and the lavish caves. So is a two-way battle between pirate ships, complete with bombs blazing and ample explosions, that has no idea when to quit.

Director Gore Verbinski, along with screenwriters Ted Elliott and Terry Rossio (2001's "Shrek"), are smart-minded and natural in their initial story set-up, but the longer the movie plays at, the more flaws become apparent. Most prominently, the goal of the heroes to stop the pirates from achieving mortality is nonsensical, because if they were mortal, at least they could be defeated and killed. And naturally, it is expected that pirate movies, a mostly forgotten genre that hasn't had a success in well over a decade, should hold taut swordfights, death-defying stunts, and at least one scene where someone is forced to walk the plank. "Pirates of the Caribbean" has these, all right, and then exhausts every single one of them by replaying variations on the same scene without any movement forward in the story. As luscious as much of the movie is, it is also burdened with a chronic long-windedness that eventually becomes tedious.

As Captain Jack Sparrow, a goofy, nearly androgynous pirate who is constantly switching sides based on his own benefits, Johnny Depp (2001's "From Hell") is a force to be reckoned with. He makes the character his own, filled with all-out originality and charm, and every time Depp is onscreen, the proceedings are better for it. The same goes for Geoffrey Rush (2002's "The Banger Sisters"), deliciously evil and over-the-top as head villain Barbossa. Keira Knightley (1999's "Star Wars: Episode I--The Phantom Menace"), who should also be known as an eerie, nearly identical doppleganger of Natalie Portman, makes for a bewitching damsel in distress who knows how to fight her own battles. The weak spot of the nain actors is Orlando Bloom (2002's "The Lord of the Rings: The Two Towers"), a bland, uncharismatic dullard. As much hype as Bloom has been getting of late, one would expect his first leading performance to not be as instantly disposable. No sparks are ignited between he and Knightley, although, in all fairness, too little time is spent on their romance for it to have much of an impact, anyway.

"Pirates of the Caribbean: The Curse of the Black Pearl"--I still can't quite get over that hideously long title--is blessed with keen filmmaking sensibilities by Gore Verbinski (even if they are not as evident as in his previous feature, "The Ring"), a visual creativity, and almost seamless visual effects. The skeletons, done with CG, move smoothly, realistically, and without the herky-jerky motions that often plague computer-created beings. Ultimately, what begins so well soon becomes too much of a good thing in every department. By the end, the film has gone from being a cheesy delight to an aimless, tired smorgasbord of empty action scenes.