"The Ninth Gate," an alleged mystery-thriller from famed, yet controversial, director Roman Polanski (1968's "Rosemary's Baby," 1974's "Chinatown"), is a wildly overlong 133-minutes sludge through well-worn territory and predictable twists and turns, seemingly leading up to a whopper of an ending. But the ending never arrives; the screen just fades to white, then to black, and the credits roll, before you have even seen anything that would make you care one way or the other about the fate of the protagonist and the predicament he is in.

Boris Balkan (Frank Langella), a wealthy collector of Lucifer-themed relics in New York City, hires seedy book dealer Dean Corso (Johnny Depp) for a well-compensated mission: travel to Europe, weed out the other two copies of a treasured, potentially dangerous book he owns, the 17th-century satanic text entitled "The Nine Gates of the Kingdom of Shadows," and investigate which of the three copies is the original. Containing the power to summon the Devil, Corso must work fast to find them, for whoever owns one of the books may very well be plotting the end of the world.

Based on the novel, "El Club Dumas," by Arturo Perez-Reverte, "The Ninth Gate" drags out its only somewhat intriguing investigation to ridiculous lengths, slowly--and I mean slowly--moving from one scene to the next. It is only in retrospect that you realize just how superfluous much of the film is, as Corso learns very little throughout, and is so dense that the viewer always knows more than he does (which isn't much to know, to begin with). Following an appropriately deliberate prologue and a superbly realized and entrancing opening credits sequence, with a memorably sumptuous music score by Wojciech Kilar, the film goes straight into downtime, and stays there for over an hour, treading through tedious scenes of meaningless exposition that don't get Corso anywhere further in his search.

The second hour of the film picks up considerably, as you finally are treated to scenes that incredibly seem to be leading somewhere, even when they aren't. There are a few chase sequences placed within the running time to add a little action to the arduous proceedings, and, more effectively, a handful of highly effective and tautly directed setpieces. One late moment that will intentionally be left vague as to not reveal one of the very few disturbing developments, involves Balkan in a dark and atmospheric castle, black clouds forbiddingly looming overhead. All of the striking images the film has to offer, by the way, are thanks to the always-impressive cinematography of Darius Khondji (whose work on 1999's "In Dreams" was snubbed of an Oscar nomination).

For such a world-class filmmaker, Polanski gets little support from his actors, almost all of whom turn in amateurish performances, as if they were performing in their very first movie (which is far from the truth), or had just received the script five minutes prior to when filming commenced (which may be the case, based on the evidence here). Johnny Depp appears to be playing the movie for laughs, and isn't having much fun doing it, while Lena Olin, as the alluring previous owner of one of the books, slinks her way through her scenes and doesn't pay attention to such a thing as "good" acting. Of the major characters, only Emmanuelle Seigner, who happens to be Polanski's younger wife, spices up the goings-on. As a mysterious traveler that keeps running into Corso during his trip, and then finally is revealed to know more about "The Nine Gates" than meets the eye, Seigner adds much-needed life to a picture that, without her and a few select technical credits, would be as dead as a doornail.

"The Ninth Gate" wants to be a horror movie, and Polanski apparently is attempting to recapture the acclaim he received from his first satanic-themed motion picture, "Rosemary's Baby," but he has no such luck. That 1968 classic chiller offered an outstanding performance from Mia Farrow, and was filled with a lumbering sense of dread and fear, two things that are largely absent from "The Ninth Gate."