It's hard to know quite what to make of "Cloud Atlas," adapted and directed by Lana and Andy Wachowski ("The Matrix") and Tom Tykwer ("Run Lola Run," "Perfume: The Story of a Murderer") — for ambition alone, you want to give this elaborate production the benefit of the doubt. But, particularly as the film draws near the three-hour mark, it stumbles, lost under its own weight. There are moments when it works wonderfully, but too many where it feels overlong and ponderous.

David Mitchell's 2004 novel, on which the movie is based, is the type of book generally called unfilmable. Told in six nesting stories, with six different narrative voices and set in six different locations and time periods (two of them far in the future), it's a mesmerizing read and a remarkable achievement, even as some of it remains mystifyingly obscure.

Its structure is elegant: We're given the first half of five stories, in chronological order, with the sixth (the one set farthest in the future) told in its entirety as a centerpiece, then the five resolved in reverse order. (To express it numerically: 1,2,3,4,5,6,5,4,3,2,1.) The movie keeps the stories but ditches the structure; it's all whooshed together in short chunks, meaning that just as the viewer starts to get attached to a story, it morphs into another one.

Another of the movie's "tricksy gimmicks" (a phrase used by a delightfully pompous book editor in the movie, played by Jim Broadbent): using the same troupe of actors in each story, sometimes so heavily made up as to be unrecognizable. (Hugh Grant, in old-age makeup as Broadbent's brother, is not a sight you'll easily forget; likewise Hugo Weaving as a female Nurse Ratched type.) It's fun to play spot-the-actor in the various stories, and it seems tied in to the vague theme of interconnectedness and souls transmigrating — but yes, it's a gimmick all the same.

As with most movies that tie linked stories together, some are more compelling than others.

Ben Whishaw is irresistible as a young musician in 1936 London, serving as amanuensis to an older, well-known composer (Broadbent); this section also introduces a haunting piece of music (the "Cloud Atlas Sextet," composed by Twyker) that wanders elsewhere in the film.

Broadbent is wonderfully blustery in a tale of revenge and escape set in contemporary England, and Jim Sturgess shines in the 1849 section, as a fragile traveler confronted with a moral dilemma. But Tom Hanks and Halle Berry speak a dialect so garbled and mystifying in the 2321 and 2346 segments, it's near-impossible to follow (easier in the book); and the 1973 thriller in which Berry stars never quite gels.

You watch "Cloud Atlas" marveling at its sweep, its elegant photography (by John Toll and Frank Griebe), its music, its moving moments of connection. But ultimately, its message of "from womb to tomb, we are bound to others, past or present" doesn't seem like quite enough to justify all the effort, both from the filmmakers and from us. It's an impressive attempt, but ultimately "Cloud Atlas" remains pagebound.

Moira Macdonald: 206-464-2725 or mmacdonald@seattletimes.com