Ten years ago director Christopher Nolan unleashed Memento, one of the most brilliant cinematic puzzles ever created. A decade on, now a Hollywood superstar as director of the Batman franchise, Nolan offers up another cinematic Rubik's Cube to perplex and intrigue. Inception builds a world of dreams within dreams and challenges the audience to follow. Whether you love the puzzle or wish you'd never started the damn thing, you have to give Nolan credit. Few other summer blockbusters will ask audiences to put down the popcorn and pay attention.

Inception stars Leo Di Caprio as Cobb and Joseph Gordon-Levitt as his partner, Arthur. They are extractors -- people who enter dreams in order to steal vital information from the subconscious minds of their sleeping targets. Hey, it's a living. The film's opening scenes set the tone with Cobb and Arthur locked in a tense negotiation with a businessman named Saito (Ken Watanabe), in a place that may be a dream or perhaps a dream within a dream.

And that's just for starters.

Before we're through there will be a dream within a dream within a dream, and below that a fourth level of dreaming limbo. Never mind the plot twists -- think of the zoning issues.

Wake up and pay attention

Saito hires Cobb and Arthur to pull off something more difficult than mere information retrieval. He wants "inception" -- to plant an idea in someone's subconscious brain and make that person believe it is their own. The target is a young business mogul named Fischer (Cillian Murphy). Cobb and Arthur must convince Fischer -- or make him convince himself -- to break up his late father's business empire.

Cobb and Arthur hire a team including Ariadne (Ellen Page), a brilliant young student whose job is to create the architecture of the dream world, like the city planner of Nappy Town. Tom Hardy and Dileep Rao play members of the Slumber Land Swat Team in charge of logistics and sedation and such.

Complications? There are a few, none bigger than Cobb's wife, Mal. Played by Oscar-winner Marion Cotillard, Mal is, in the corporeal world, deceased. But in Nod, she's everywhere. And she's trouble. Cobb has plenty of unresolved issues surrounding his wife's death. Some of those issues are causing him real-world problems, such as an inability to return to the States to see his children.

Professionally, Cobb's wife issues threaten everything his team is attempting to do. She has this way of showing up in Cobb's subconscious, pursuing her own agenda. It all has to do with their murky past and just how Mal ended up dead. Cobb must deal with his personal history or risk sabotaging the whole dreamy operation.

Meeting of minds

The cast also includes Michael Caine, Tom Berenger, Pete Postlethwaite and Lukas Haas. Nolan and company have some fun along the way. Check out the musical cue intended to bring the dreamers back to reality: Non, Je Regrette Rien, the signature tune of Edith Piaf, the tragic French icon whose biopic brought Cotillard her Best Actress Oscar.

Then there's the initial establishing shot of Paris, panning across the rooftops to take in that famous landmark -- the Sacre Coeur cathedral. Nolan may be the first filmmaker in history to switch up Paris landmarks on us. (Alas, Mr. Eiffel's creation shows up a little later. Even in dreams, you can't break too many rules.)

Setting a movie in dreamland is a challenge that has defeated more than one filmmaker's imagination. The usual approach is to go all Dali-esque, a temptation Nolan largely avoids. In fact, despite some suspension of the laws of time and physics, Nolan's dream world is remarkably mundane for the most part. Perhaps the plot allows for this, since these dreams have actually been constructed by an outside architect in order to seem like reality. But the sleeping world of Inception rarely conveys any of the wondrous, frightening quality of dreams and nightmares, which seems like a lost opportunity.

Instead the movie creates a set of rules that govern the dream world. Grasping the rules helps you understand the plot. But it doesn't lend Inception the magical feel it might have had.

Inception requires vigilance to follow the bread crumb trail leading from one dream to the next and the next. What will make the movie succeed or fail for you is whether that concentration seems worth the effort. The emotional heart of Inception is the story of Cobb and Mal. If you buy into it, Inception will seem like a work of genius. If it leaves you cold, Nolan's film will seem like a large, expensive Rube Goldberg contraption -- impressive in its way, but ultimately pointless.