Back in 2003, the concept of a theme park ride becoming a multi-billion dollar movie franchise sounded ridiculous to every sane person on the planet.

Yet, "Pirates of the Caribbean" continues to dominate the box office. Most of the credit has rightfully gone to its top star Johnny Depp, who has played the mischievous Captain Jack Sparrow through four installments, including the latest, "On Stranger Tides." It's a dynamic and unique performance, deserving placement alongside some of the greatest characters in screen history.

Most consider the first film, "The Curse of the Black Pearl," to be the best of the bunch, which it is, but I've also enjoyed the less popular sequels, "Dead Man's Chest" and "At World's End." Critics ravaged these films, calling them convoluted, overlong and preposterous.

No argument here. That's exactly why I love them.

I love the lunacy of "Dead Man's Chest," particularly how director Gore Verbinski escalates the action to cartoonish levels. The villain has a slimy octopus face, and the climatic sword fight takes place on a giant hamster wheel. It's a carnival of a movie, and Depp dashes through it with the energy of a small child.

"At World's End" took an even harsher pummeling from critics and audiences, mostly because of its bloated three-hour running length and a plot that required 10 times the concentration of a typical summer blockbuster. I remain convinced the story makes sense to those paying attention, and I enjoy how every major character ends up double and triple-crossing each other by the end.

Don't get me wrong. I don't think either film is particularly good. They both can't hold a candle to the original film, which managed to mix mystical adventure with kooky humor in a way that hasn't been matched since. But I appreciate how the sequels attempt something grander than the typical Hollywood follow-up. They are pure insanity, with Depp's behavior getting more and more bizarre as it goes along.

Perhaps my appreciation of the previous sequels is the reason I am so disappointed with "On Stranger Tides," a movie that ditches several characters and subplots in favor of a straightforward sea race to the Fountain of Youth.

The acting is certainly there: In addition to the always reliable Depp, Ian McShane, Penelope Cruz and the reliably hammy Geoffrey Rush infuse the new film with some of that swashbuckling spirit of the original.

The story, however, is just too pedestrian. Other than a fun opening sequence in London and a nifty encounter with ravenous mermaids, "On Stranger Tides" takes a most predictable path to its underwhelming climax.

Director Rob Marshall ("Chicago") takes over for exiting franchise player Verbinski, and the result is decidedly mixed. For a guy so experienced in musical showmanship, "On Stranger Tides" has no rhythm. The movie drags in spots, and the numerous action sequences are choppy and uninvolving.

For a movie so focused on Captain Jack, Depp feels restrained in this outing. The character has a few classic bits here and there, but too often Sparrow is required to drive the story forward and behave like a typical big screen hero.

The worst thing you can do to Captain Jack is make him a steady and reliable protagonist.

"On Stranger Tides" isn't exactly a bad movie. After the last two films, many viewers might appreciate this more straightforward adventure. Captain Jack is still (mostly) the Captain Jack we love, and there are moments of fun sprinkled throughout.

To me, however, this is the first film in the franchise that feels rehashed. I want more double-crosses. I want more ridiculous sea creatures. I want Michael Bolton in there dressed as a pirate. The crazier, the better.

Tyler Wilson can be reached at twilson@cdapress.com. Sponsored by the Hayden Cinema 6 Theater.